# Thirty Years' War

vteThirty Years' War :
Bohemian Revolt (1618–1620)
Pilsen
Lomnice
Sablat
Wisternitz
Bautzen
White Mountain
Neu Titschein
Palatinate campaign (1620–1623)
Bad Kreuznach
Oppenheim
Bacharach
Jülich
Mingolsheim
Wimpfen
Höchst
Bergen op Zoom
Heidelberg
Fleurus
Mannheim
Frankenthal
Stadtlohn
Transylvanian invasions of Hungary (1619–1621, 1623–1624, 1626)
Humenné
Érsekújvár
Tyrnau [de]
Hodonín
Vlach uprisings
Danish intervention (1625–1629)
Breda
Dessau Bridge
Oldenzaal
Lutter am Barenberge
Groenlo
Stralsund
Wolgast
's-Hertogenbosch
Swedish intervention (1630–1635)
Swedish landing
Frankfurt
Magdeburg
Werben
1st Breitenfeld
Bamberg
Rain
Maastricht
Nuremberg
Wiesloch
Alte Veste
Fürth
Lützen
Oldendorf
Pfaffenhofen
Steinau
Konstanz
1st Breisach
1st Rheinfelden
Liegnitz [de]
1st Nördlingen
Strasbourg Bridge
Swedish-French Period (1635–1648)
Les Avins
Leuven
Schenkenschans
Ray-sur-Saône
Dömitz [de]
Haselünne [de]
Raon
Tornavento
2nd Magdeburg
Somme
Wittstock
2nd Breda
Venlo
Leipzig
Hanau
2nd Rheinfelden
Saint Omer
Fuenterrabía
Kallo
Wittenweiher
Thann [de]
Vlotho
2nd Breisach
1st Freiberg
Chemnitz
Melnik
Thionville
Salses
Cambrils
Montjuïc
Preßnitz
Plauen
La Marfée
Dorsten
Wolfenbüttel
Kempen
Honnecourt
Schweidnitz
2nd Breitenfeld
2nd Freiberg
Rocroi
1st Brno
Tuttlingen
Kolding
Freiburg
Philippsburg
Jüterbog
Bysjön
Jankau
2nd Brno
Mergentheim
2nd Nördlingen
3rd Hulst
Korneuburg [de]
Totenhöhe [de]
Hohentübingen [de]
Mardyck
Dunkirk
Triebl
Naples
Zusmarshausen
Wevelinghoven
Lens
Dachau [de]
Prague
Naval battles
Gibraltar
Genoa
The Slaak
1st Saint Martin
Lizard Point
Dunkirk
Channel
The Downs
Cape St. Vincent
2nd Saint Martin
Lister Dyb
Colberger Heide
Fehmarn :
$_{Treaties}$ :
The Thirty Years' War, fought primarily in Central Europe between 1618 and 1648, was one of the most destructive conflicts in European history. An estimated 4.5 to 8 million soldiers and civilians died from battle, famine, or disease, while parts of Germany reported population declines of over 50%. Related conflicts include the Eighty Years' War, the War of the Mantuan Succession, the Franco-Spanish War, the Torstenson War, the Dutch-Portuguese War, and the Portuguese Restoration War.
The war began as a continuation of the religious conflict initiated by the 16th-century Reformation within the Holy Roman Empire. The 1555 Peace of Augsburg attempted to resolve this by dividing the Empire into Catholic and Lutheran states, but over the next 50 years the expansion of Protestantism destabilised the settlement. While differences over religion and imperial authority were important factors in causing the war, some commentators suggest its scope and extent were driven by the contest for European dominance between Habsburg-ruled Spain and Austria, and the French House of Bourbon.
Its outbreak is generally traced to 1618, when the Catholic Emperor Ferdinand II was replaced as king of Bohemia by the Protestant Frederick V of the Palatinate. Although the Bohemian Revolt was quickly suppressed, Frederick's participation expanded the fighting into the Palatinate, whose strategic importance drew in the Dutch Republic and Spain, then engaged in the Eighty Years' War. In addition, the acquisition of territories within the empire by rulers like Christian IV of Denmark and Gustavus Adolphus of Sweden gave them and other foreign powers an ongoing motive to intervene. Combined with fears the Protestant religion in general was threatened, it turned an internal dynastic dispute into a European conflict.
The period from 1618 to 1635 was primarily a civil war within the Holy Roman Empire, with support from external powers. After 1635, the empire became one theatre in a wider struggle between France, chiefly supported by Sweden, and Emperor Ferdinand III, whose principal ally was Spain. Fighting ended with the 1648 Peace of Westphalia, the terms of which included greater autonomy within the empire for states like Bavaria and Saxony, as well as acceptance of Dutch independence by Spain. The conflict shifted the balance of power in favour of France, and set the stage for the expansionist wars of Louis XIV which dominated Europe for the next sixty years.

## Structural origins

The 16th century Reformation caused open warfare between Protestants and Catholics within the Holy Roman Empire, which ended with the 1552 Peace of Passau. The Peace of Augsburg in 1555 tried to prevent a recurrence by fixing boundaries between the two faiths, using the principle of cuius regio, eius religio. Under this, states were designated as either Lutheran, then the most usual form of Protestantism, or Catholic, based on the religion of their ruler. Other provisions protected substantial religious minorities in cities like Donauwörth, and confirmed Lutheran ownership of property taken from the Catholic Church since 1552.
However, the settlement was undermined by the expansion of Protestantism into Catholic areas post 1555, particularly Calvinism, a Protestant doctrine viewed with hostility by both Lutherans and Catholics. The Augsburg terms also gave individual rulers significantly greater autonomy, allowing larger states to pursue their own objectives. These frequently clashed with those of central authority, and on occasion superseded religion, with the Protestant states of Saxony, Brandenburg, Denmark–Norway and Sweden competing over the lucrative Baltic trade.
Reconciling these differences was hampered by fragmented political institutions, which included 300 imperial estates distributed across Germany, the Low Countries, northern Italy, and present-day France. These ranged in size and importance from the seven prince-electors who voted for the Holy Roman Emperor, down to prince-bishoprics and imperial cities like Hamburg. Each also belonged to a regional grouping or "imperial circle", which primarily focused on defence and operated independently of the others. Above all of these was the Imperial Diet, which assembled infrequently, and focused on discussion, rather than legislation.
Although technically elected, since 1440 the position of Emperor had been held by the House of Habsburg. The largest single landowner within the Holy Roman Empire, they ruled over eight million subjects, based in territories that included Austria, Bohemia and Hungary. They also controlled the Spanish Empire until 1556, when Charles V divided the two states between different branches of the family. This bond was reinforced by frequent inter-marriage, while Spain retained territories within the Holy Roman Empire such as the Spanish Netherlands, Milan and Franche-Comté. Although the two often collaborated, their objectives did not always align. Spain was a global maritime superpower, stretching from Europe to the Philippines, and the Americas, while Austria was a land-based power, focused on Germany, and securing their eastern border against the Ottoman Empire.
Prior to the Reformation, common religion helped compensate for weak Imperial institutions. After 1556, rising religious and political tensions allowed states like Lutheran Saxony and Catholic Bavaria to expand their own power, while further weakening imperial authority. This internal political struggle was exacerbated by external powers with their own strategic objectives, such as Spain, the Dutch Republic, or France, confronted by Habsburg lands on its borders to the north, south, and along the Pyrenees. Since a number of foreign rulers were also imperial princes, divisions within the empire drew in players like Christian IV of Denmark, who joined the war in 1625 as Duke of Holstein-Gottorp.

## Background: 1556 to 1618

Disputes occasionally resulted in full-scale conflict like the 1583 to 1588 Cologne War, caused when its ruler converted to Calvinism. More common were events such as the 1606 "Battle of the Flags" in Donauwörth, when riots broke out after the Lutheran majority blocked a Catholic religious procession. Emperor Rudolf approved intervention by the Catholic Maximilian of Bavaria. In return, he was allowed to annex the town, and as agreed at Augsburg, the official religion changed from Lutheran to Catholic.
When the Imperial Diet opened in February 1608, both Lutherans and Calvinists sought re-confirmation of the Augsburg settlement. In return, the Habsburg heir Archduke Ferdinand required the immediate restoration of any property taken from the Catholic Church since 1555, rather than the previous practice whereby each case was assessed separately. By threatening all Protestants, his demand paralysed the diet, and removed the perception of imperial neutrality.
Loss of faith in central authority meant towns and rulers began strengthening their fortifications and armies; outside travellers often commented on the growing militarisation of Germany in this period. In 1608, Frederick IV, Elector Palatine formed the Protestant Union, and Maximilian responded by setting up the Catholic League in July 1609. Both were created to support the dynastic ambitions of their leaders, but combined with the 1609 to 1614 War of the Jülich Succession, the result was to increase tensions throughout the empire. Some historians who see the war as primarily a European conflict argue Jülich marks its beginning, with Spain and Austria backing the Catholic candidate, France and the Dutch Republic the Protestant.
External powers became involved in what was an internal German dispute due to the imminent expiry of the 1609 Twelve Years' Truce, which suspended the Eighty Years' War between Spain and the Dutch Republic. Before restarting hostilities, Ambrosio Spinola, commander in the Spanish Netherlands, needed to secure the Spanish Road, an overland route connecting Habsburg possessions in Italy to Flanders. This allowed him to move troops and supplies by road, rather than sea where the Dutch navy was dominant; by 1618, the only part not controlled by Spain ran through the Electoral Palatinate.
Since Emperor Matthias had no surviving children, in July 1617 Philip III of Spain agreed to support Ferdinand's election as king of Bohemia and Hungary. In return, Ferdinand made concessions to Spain in northern Italy and Alsace, and agreed to support their offensive against the Dutch. Doing so required his election as emperor, which was not guaranteed; Maximilian of Bavaria, who opposed the increase of Spanish influence in an area he considered his own, tried to create a coalition with Saxony and the Palatinate to support his candidacy.
Another option was Frederick V, Elector Palatine, a Calvinist who succeeded his father in 1610, and in 1613 married Elizabeth Stuart, daughter of James I of England. Four of the electors were Catholic, and three were Protestant; if this balance changed, it would potentially result in the election of a Protestant emperor. When Ferdinand became king of Bohemia in 1617, he also gained control of its electoral vote; however, his conservative Catholicism made him unpopular with the predominantly Protestant nobility, who were also concerned about the erosion of their rights. These factors combined to bring about the Bohemian Revolt in May 1618.

## Phase I: 1618 to 1635
### Bohemian Revolt

Ferdinand once claimed he would rather see his lands destroyed than tolerate heresy within them. Less than 18 months after taking control of Styria in 1595, he had eliminated Protestantism in what had been a stronghold of the Reformation. Absorbed by their war in the Netherlands, his Spanish relatives preferred to avoid antagonising Protestants elsewhere. They recognised the dangers associated with Ferdinand's fervent Catholicism, but supported his claim due to the lack of alternatives.
On being elected king of Bohemia in May 1617, Ferdinand reconfirmed Protestant religious freedoms, but his record in Styria led to the suspicion he was only awaiting a chance to overturn them. These concerns were heightened after a series of legal disputes over property were all decided in favour of the Catholic Church. In May 1618, Protestant nobles led by Count Thurn met in Prague Castle with Ferdinand's two Catholic representatives, Vilem Slavata and Jaroslav Borzita. In what became known as the Third Defenestration of Prague, both men were thrown out of the castle windows along with their secretary Filip Fabricius, although all three survived.
Thurn established a Protestant-dominated government in Bohemia, while unrest expanded into Silesia and the Habsburg heartlands of Lower and Upper Austria, where much of the nobility was also Protestant. Losing control of these threatened the entire Habsburg state, while Bohemia was one of the most prosperous areas of the Empire and its electoral vote crucial to ensuring Ferdinand succeeded Matthias as Emperor. The combination meant their recapture was vital for the Austrian Habsburgs but chronic financial weakness left them dependent on Maximilian and Spain for the resources needed to achieve this.
Spanish involvement inevitably drew in the Dutch, and potentially France, although the strongly Catholic Louis XIII of France faced his own Protestant rebels at home and refused to support them elsewhere. The revolt also provided opportunities for external opponents of the Habsburgs, including the Ottoman Empire and Savoy. Funded by Frederick and Charles Emmanuel I, Duke of Savoy, a mercenary army under Ernst von Mansfeld was sent to support the Bohemian rebels. Attempts by Maximilian and John George of Saxony to broker a negotiated solution ended when Matthias died in March 1619, since many believed the loss of his authority and influence had fatally damaged the Habsburgs.
By mid-June 1619, the Bohemian army under Thurn was outside Vienna and although Mansfeld's defeat by imperial forces at Sablat forced him to return to Prague, Ferdinand's position continued to worsen. Gabriel Bethlen, Calvinist Prince of Transylvania, invaded Hungary with Ottoman support, although the Habsburgs persuaded them to avoid direct involvement; this was helped when the Ottomans became involved in the 1620 Polish war, followed by the 1623 to 1639 conflict with Persia.
On 19 August, the Bohemian Estates rescinded Ferdinand's 1617 election as king; on the 26th, they formally offered the crown to Frederick. Two days later, Ferdinand was elected emperor, making war inevitable if Frederick accepted the Bohemian Crown. Most of Frederick's advisors urged him to reject it, as did the Duke of Savoy, and his father-in-law James I. The exceptions included Christian of Anhalt and Maurice of Orange, for whom conflict in Germany was a means to divert Spanish resources from the Netherlands. The Dutch offered subsidies to Frederick and the Protestant Union, helped raise loans for Bohemia, and provided weapons and munitions.
However, wider European support failed to materialise, largely due to lack of enthusiasm for removing a legally elected ruler, regardless of religion. Although Frederick accepted the crown and entered Prague in October 1619, his support eroded over the next few months. In July 1620, the Protestant Union proclaimed its neutrality, while John George of Saxony backed Ferdinand in return for the cession of Lusatia, and a guarantee of Lutheran rights in Bohemia. Maximilian of Bavaria funded a combined Imperial-Catholic League army led by Count Tilly and Charles of Bucquoy, which pacified Upper and Lower Austria and occupied western Bohemia before marching on Prague. Defeated by Tilly at the Battle of White Mountain in November 1620, the Bohemian army disintegrated, and Frederick was forced to flee the country.

### Palatinate Campaign

By abandoning Frederick, the German princes had hoped to restrict the dispute to Bohemia, but this was thwarted by Maximilian's dynastic ambitions. In the October 1619 Treaty of Munich, Ferdinand transferred the Palatinate's electoral vote to Bavaria, and allowed Maximilian to annex the Upper Palatinate. Many Protestants had supported Ferdinand because in principle they opposed the deposition of a legally elected ruler, and now objected to Frederick's removal on the same grounds. For Catholics, it presented an opportunity to regain lands and properties lost since 1555, a combination which destabilised large parts of the Empire.
At the same time, the Spanish were drawn into the conflict due to the strategic importance of the Spanish Road for their war in the Netherlands, and its proximity to the Palatinate. When an army led by Córdoba occupied the Lower Palatinate in October 1619, James I responded to this attack on his son-in-law. English naval forces were sent to threaten Spanish possessions in the Americas and the Mediterranean, while James announced he would declare war if Spanish troops were not withdrawn by spring 1621. These actions were primarily designed to placate his opponents in Parliament, who considered his pro-Spanish policy a betrayal of the Protestant cause. Spanish chief minister Olivares correctly interpreted them as an invitation to open negotiations, and in return for an Anglo-Spanish alliance offered to restore Frederick to his Rhineland possessions.
Since Frederick's demand for full restitution of his lands and titles was incompatible with the Treaty of Munich, hopes of a negotiated peace quickly evaporated. Despite defeat in Bohemia, Frederick's allies included Georg Friedrich of Baden and Christian of Brunswick, while the Dutch provided him with military support after the Eighty Years' War restarted in April 1621 and his father-in-law James funded an army of mercenaries under Mansfeld. However, their failure to co-ordinate effectively led to a series of defeats by Spanish and Catholic League forces, including Wimpfen in May 1622 and Höchst in June. By November 1622, Spanish and Imperial troops controlled most of the Palatinate, apart from Frankenthal, which was held by a small English garrison under Sir Horace Vere. The remnants of Mansfeld's army took refuge in the Dutch Republic, as did Frederick, who spent most of his time in The Hague until his death in November 1632.
At a meeting of the Imperial Diet in February 1623, Ferdinand forced through provisions transferring Frederick's titles, lands, and electoral vote to Maximilian. He did so with support from the Catholic League, despite strong opposition from Protestant members, as well as the Spanish. The Palatinate was clearly lost; in March, James instructed Vere to surrender Frankenthal, while Tilly's victory over Christian of Brunswick at Stadtlohn in August completed military operations. However, Spanish and Dutch involvement in the campaign was a significant step in internationalising the war, while Frederick's removal meant other Protestant princes began discussing armed resistance to preserve their own rights and territories.

### Danish intervention (1625–1629)

With Saxony dominating the Upper Saxon Circle and Brandenburg the Lower, both kreise had remained neutral during the campaigns in Bohemia and the Palatinate. However, Frederick's deposition in 1623 meant John George of Saxony and the Calvinist George William, Elector of Brandenburg became concerned Ferdinand intended to reclaim formerly Catholic bishoprics currently held by Protestants. These fears seemed confirmed when Tilly restored the Roman Catholic Diocese of Halberstadt in early 1625.
As Duke of Holstein, Christian IV was also a member of the Lower Saxon circle, while the Danish economy relied on the Baltic trade and tolls from traffic through the Øresund. In 1621, Hamburg accepted Danish "supervision", while his son Frederick became joint-administrator of Lübeck, Bremen, and Verden; possession ensured Danish control of the Elbe and Weser rivers.
Ferdinand had paid Albrecht von Wallenstein for his support against Frederick with estates confiscated from the Bohemian rebels, and now contracted with him to conquer the north on a similar basis. In May 1625, the Lower Saxony kreis elected Christian their military commander, although not without resistance; Saxony and Brandenburg viewed Denmark and Sweden as competitors, and wanted to avoid either becoming involved in the empire. Attempts to negotiate a peaceful solution failed as the conflict in Germany became part of the wider struggle between France and their Habsburg rivals in Spain and Austria.
In the June 1624 Treaty of Compiègne, France had agreed to subsidise the Dutch war against Spain for a minimum of three years, while in the December 1625 Treaty of The Hague, the Dutch and English agreed to finance Danish intervention in the Empire. Hoping to create a wider coalition against Ferdinand, the Dutch invited France, Sweden, Savoy, and the Republic of Venice to join, but it was overtaken by events. In early 1626, Cardinal Richelieu, main architect of the alliance, faced a new Huguenot rebellion at home and in the March Treaty of Monzón, France withdrew from northern Italy, re-opening the Spanish Road.
Dutch and English subsidies enabled Christian to devise an ambitious three part campaign plan; while he led the main force down the Weser, Mansfeld would attack Wallenstein in Magdeburg, supported by forces led by Christian of Brunswick and Maurice of Hesse-Kassel. The advance quickly fell apart; Mansfeld was defeated at Dessau Bridge in April, and when Maurice refused to support him, Christian of Brunswick fell back on Wolfenbüttel, where he died of disease shortly after. The Danes were comprehensively beaten at Lutter in August, and Mansfeld's army dissolved following his death in November.
Many of Christian's German allies, such as Hesse-Kassel and Saxony, had little interest in replacing imperial domination with Danish, while few of the subsidies agreed to by the Treaty of The Hague were ever paid. Charles I of England allowed Christian to recruit up to 9,000 Scottish mercenaries, but they took time to arrive, and while able to slow Wallenstein's advance were insufficient to stop him. By the end of 1627, Wallenstein occupied Mecklenburg, Pomerania, and Jutland, and began making plans to construct a fleet capable of challenging Danish control of the Baltic. He was supported by Spain, for whom it provided an opportunity to open another front against the Dutch.
On 13 May 1628, his deputy von Arnim besieged Stralsund, the only port with facilities large enough to build this fleet. However, this threat led Gustavus Adolphus to send several thousand Scots and Swedish troops to Stralsund, commanded by Alexander Leslie who was also appointed governor. Von Arnim was forced to lift the siege on 4 August, but three weeks later, Christian suffered another defeat at Wolgast. He began negotiations with Wallenstein, who despite his recent victories was concerned by the prospect of Swedish intervention, and thus anxious to make peace.
With Austrian resources stretched by the outbreak of the War of the Mantuan Succession, Wallenstein persuaded Ferdinand to agree with relatively lenient terms in the June 1629 Treaty of Lübeck. Christian retained his German possessions of Schleswig and Holstein, in return for relinquishing Bremen and Verden, and abandoning support for the German Protestants. While Denmark kept Schleswig and Holstein until 1864, this effectively ended its reign as the predominant Nordic state.
Once again, the methods used to obtain victory explain why the war failed to end. Ferdinand paid Wallenstein by letting him confiscate estates, extort ransoms from towns, and allowing his men to plunder the lands they passed through, regardless of whether they belonged to allies or opponents. In early 1628, Ferdinand deposed the hereditary Duke of Mecklenburg, and appointed Wallenstein in his place, an act which united all German princes in opposition, regardless of religion. This unity was undermined by Maximilian of Bavaria's desire to retain the Palatinate; as a result, the Catholic League argued only for a return to the position prevailing pre-1627, while Protestants wanted that of 1618.
Made overconfident by success, in March 1629 Ferdinand passed an Edict of Restitution, which required all lands taken from the Catholic church after 1555 to be returned. While technically legal, politically it was extremely unwise, since doing so would alter nearly every single state boundary in north and central Germany, deny the existence of Calvinism and restore Catholicism in areas where it had not been a significant presence for nearly a century. Well aware none of the princes involved would agree, Ferdinand used the device of an imperial edict, once again asserting his right to alter laws without consultation. This new assault on "German liberties" ensured continuing opposition and undermined his previous success.
At the same time, his Spanish allies were reluctant to antagonise German Protestants as their war in the Spanish Netherlands had now shifted in favour of the Dutch Republic. The financial predicament of the Spanish Crown steadily deteriorated in the 1620s, particularly after the Dutch West India Company captured their treasure fleet at Matanzas in 1628. The War of the Mantuan Succession further diverted Spanish resources from the Netherlands, while the loss of 's-Hertogenbosch to the Dutch Army under Frederick Henry in 1629 caused dismay in Madrid.

### Sweden invades Germany (1630–1635)

From 1626 to 1629, Gustavus was engaged in a war with Poland–Lithuania, ruled by his Catholic cousin Sigismund, who also claimed the Swedish throne and was backed by Ferdinand II. Once this conflict ended, and with only a few minor states like Hesse-Kassel still openly opposing Ferdinand, Gustavus became an obvious ally for Richelieu. In September 1629, the latter helped negotiate the Truce of Altmark between Sweden and Poland, freeing Gustavus to enter the war. Partly a genuine desire to support his Protestant co-religionists, like Christian he also wanted to maximise his share of the Baltic trade that provided much of Sweden's income.
Following failed negotiations with Ferdinand II, Gustavus landed in Pomerania in June 1630 with nearly 18,000 Swedish troops. Using Stralsund as a bridgehead, he marched south along the Oder towards Stettin and coerced Bogislaw XIV, Duke of Pomerania, into agreeing an alliance which secured his interests in Pomerania against his rival Sigismund. As a result, the Poles turned their attention to Russia, initiating the 1632 to 1634 Smolensk War.
However, Swedish expectations of widespread German support proved unrealistic. By the end of 1630, their only new ally was the Administrator of Magdeburg, Christian William whose capital was under siege by Tilly. Despite the devastation inflicted by Imperial soldiers, Saxony and Brandenburg had their own ambitions in Pomerania, which clashed with those of Gustavus; previous experience also showed inviting external powers into the Empire was easier than getting them to leave.
Gustavus put pressure on Brandenburg by sacking Küstrin and Frankfurt an der Oder, while the Sack of Magdeburg in May 1631 provided a powerful warning of the consequences of Imperial victory. Once again, Richelieu used French financial power to bridge differences between the Swedes and the German princes; the 1631 Treaty of Bärwalde provided funds for the Swedes and their Protestant allies, including Saxony and Brandenburg. These amounted to 400,000 Reichstaler per year, or one million livres, plus an additional 120,000 for 1630. While less than 2% of total French income, these payments boosted that of Sweden by more than 25%, and allowed Gustavus to maintain 36,000 troops.
Gustavus used this army to win victories at Breitenfeld in September 1631, then Rain in April 1632, where Tilly was killed. Ferdinand turned once again to Wallenstein, who realised Gustavus was overextended and established himself at Fürth, from where he could threaten his supply lines. This led to the Battle of the Alte Veste in late August, one of the largest battles of the war. An assault on the Imperial camp outside the town was bloodily repulsed, arguably the greatest blunder committed by Gustavus during his German campaign.
Two months later, the Swedes fought an Imperial army at Lützen. Both sides suffered heavy casualties, while Gustavus himself was killed and some Swedish units incurred losses of over 60%. Fighting continued until dusk when Wallenstein retreated, abandoning his artillery and wounded. Despite their losses, this allowed the Swedes to claim victory, although the result continues to be disputed.
After his death, Gustavus' policies were continued by his Chancellor Axel Oxenstierna, and with French backing, Sweden and their German allies formed the Heilbronn League in April 1633. In July, their combined forces defeated an Imperial army under Bronckhorst-Gronsfeld at Oldendorf. Critics claimed this defeat was caused by Wallenstein's failure to support the Bavarians, while rumours spread that he was preparing to switch sides. As a result, Ferdinand II ordered his arrest in February 1634, and on 25th, he was assassinated by his own officers in Cheb.
The loss of Wallenstein and his organisation left Ferdinand II reliant on Spain for military support. Since their main concern was to re-open the Spanish Road for their campaign against the Dutch, the focus of the war now shifted from the north to the Rhineland and Bavaria. Cardinal-Infante Ferdinand of Austria, new Governor of the Spanish Netherlands, raised an army of 18,000 in Italy, which met up with an Imperial force of 15,000 at Donauwörth on 2 September 1634. Four days later, they won a decisive victory at Nördlingen which destroyed Swedish power in southern Germany and led to the defection of their German allies, who now sought to make peace with the Emperor.

## Phase II: French intervention, 1635 to 1648

Swedish defeat at Nördlingen triggered direct French intervention and thus expanded the conflict rather than ending it. Richelieu provided the Swedes with new subsidies, hired mercenaries led by Bernard of Saxe-Weimar for an offensive in the Rhineland, and in May 1635 declared war on Spain, starting the 1635 to 1659 Franco-Spanish War. A few days later, the German states and Ferdinand agreed to the Peace of Prague; in return for withdrawing the Edict of Restitution, the Heilbronn and Catholic Leagues were dissolved and replaced by a single Imperial army, although Saxony and Bavaria retained control of their own forces. This is generally seen as the point when the war ceased to be a primarily inter-German religious conflict.
In March 1635, French soldiers entered the Valtellina, cutting the link between Spanish controlled Milan and the Empire. In May, their main army of 35,000 invaded the Spanish Netherlands, but withdrew in July after suffering 17,000 casualties. In March 1636, France joined the Thirty Years War as an ally of Sweden, whose loss of most of the territories gained by Gustavus and their taxes made it increasingly reliant on French financing. The Spanish then invaded northern France, causing panic in Paris before lack of supplies forced them to retreat. Despite the defection of most of their German allies, victory under Johan Banér at Wittstock on 4 October re-established Swedish predominance in northeast Germany.
Ferdinand II died in February 1637, and was succeeded by his son Ferdinand III, who faced a precarious military position. Although Matthias Gallas had forced Banér back to the Baltic, in March 1638 Bernard of Saxe Weimar destroyed an Imperial army at Rheinfelden. His capture of Breisach in December secured French control of Alsace and severed the Spanish Road, forcing Gallas to divert resources there. Although von Hatzfeldt defeated a combined Scots-German force at Vlotho in October, lack of supplies obliged Gallas to withdraw from the Baltic.
In April 1639, Banér defeated the Saxons at Chemnitz, then entered Bohemia in May. To retrieve the situation, Ferdinand diverted Piccolomini's army from Thionville, ending direct military cooperation between Austria and Spain. Pressure grew on Olivares to make peace, especially after French and Swedish gains in Germany cut the Spanish Road, forcing Madrid to resupply their armies in Flanders by sea. Attempts to re-assert maritime control ended when the Dutch fleet under Maarten Tromp won a significant victory over the Spanish at the Downs in October 1639.
The French occupied Spanish-controlled Artois in 1640, while Dutch attacks on Portuguese colonies, combined with opposition to taxes, led to revolts in both Portugal and Catalonia. Olivares now argued Spain should accept Dutch independence, and focus on preventing further French gains in the Spanish Netherlands. This appeared achievable since most of the Dutch regenten believed the war was won, the only question being the price of peace. They therefore reduced the army budget for 1640, despite objections from Frederick Henry.
After Bernard died in July 1639, his troops joined Banér's Swedish army in an ineffectual campaign along the Weser, the highlight being a surprise attack in January 1641 on the Imperial Diet in Regensburg. Forced to retreat, Banér reached Halberstadt in May where he died, and despite beating off an Imperial force at Wolfenbüttel in June, his largely German troops mutinied due to lack of pay. The situation was saved by the arrival of Lennart Torstensson in November with 7,000 Swedish recruits and enough cash to satisfy the mutineers.
French victory at Kempen in January 1642 was followed by Second Breitenfeld in October 1642, where Torstensson inflicted almost 10,000 casualties on an Imperial army led by Archduke Leopold Wilhelm of Austria. The Swedes captured Leipzig in December, although they failed to take Freiberg, and by 1643 the Saxon army had been reduced to a few isolated garrisons. Despite these setbacks, Ferdinand fought on, hoping to improve his position enough to exclude the Imperial estates from his peace negotiations with France and Sweden, and allow him to represent the Empire as a whole.
This seemed more likely when Richelieu died in December 1642, followed by Louis XIII in May 1643, leaving his five-year-old son Louis XIV as king. However, Richelieu's policies were continued by his successor Cardinal Mazarin, while gains in Alsace allowed France to focus on the war against Spain. In 1643, the Army of Flanders invaded northern France, but were decisively beaten by Condé at Rocroi on 19 May. This ended any prospect of re-opening the Spanish Road, and Madrid finally accepted the reality of Dutch independence.
However, Condé was unable to fully exploit his victory due to factors affecting all combatants. The devastation inflicted by 25 years of warfare meant armies spent more time foraging than fighting, forcing them to become smaller and more mobile, with a much greater emphasis on cavalry. Difficulties in gathering provisions meant campaigns started later, and restricted them to areas that could be easily supplied, usually close to rivers. In addition, the French army in Germany was shattered at Tuttlingen in November by the Bavarian general Franz von Mercy.
Soon after Rocroi, Ferdinand invited Sweden and France to attend peace talks in the Westphalian towns of Münster and Osnabrück, but negotiations were delayed when Christian of Denmark blockaded Hamburg and increased toll payments in the Baltic. This severely impacted the Dutch and Swedish economies, and in December 1643 the Torstensson War began when the Swedes invaded Jutland with Dutch naval support. Ferdinand assembled an army under Gallas to attack the Swedes from the rear, which proved a disastrous decision. Leaving Wrangel to finish the war in Denmark, in May 1644 Torstensson marched into the Empire; Gallas was unable to stop him, while the Danes sued for peace after their defeat at Fehmarn in October 1644.
In August 1644, the French and Bavarian armies met in the three day Battle of Freiburg, in which both sides suffered heavy casualties. Convinced the war could no longer be won, Maximilian now put pressure on Ferdinand to end the conflict. Shortly after peace talks restarted in November, Gallas' Imperial army disintegrated and its remnants retreated into Bohemia, where they were scattered by Torstensson at Jankau in March 1645. In May, a Bavarian force under von Mercy destroyed a French detachment at Herbsthausen, before he was defeated and killed at Second Nördlingen in August. Deprived of Imperial support, John George of Saxony signed a six-month truce with Sweden in September, and in the March 1646 Treaty of Eulenberg agreed to remain neutral until the end of the war.
Under Turenne, French commander in the Rhineland, and Wrangel, who had replaced Torstensson, the French and Swedes separately invaded Bavaria in the summer of 1646. Maximilian was soon desperate to end the war he was largely responsible for starting, at which point the Spanish publicised a secret offer by Mazarin to exchange French-occupied Catalonia for the Spanish Netherlands. Angered by this duplicity, the Dutch agreed a truce with Spain in January 1647 and began to negotiate their own peace terms. Having failed to acquire the Netherlands through diplomacy, Mazarin decided to do so by force. To free up resources for the attempt, on 14 March 1647 he signed the Truce of Ulm with Bavaria, Cologne and Sweden.
The planned offensive fell apart when Turenne's mostly German troops mutinied, while Bavarian general Johann von Werth refused to comply with the truce. Although the mutinies were quickly suppressed, Maximilian felt obliged to follow Werth's example and in September ordered Bronckhorst-Gronsfeld to combine the remnants of the Bavarian army with Imperial troops under von Holzappel. Outnumbered by a Franco-Swedish army led by Wrangel and Turenne, they were defeated at Zusmarshausen in May 1648. Holzappel was killed, and although most of his army escaped thanks to Raimondo Montecuccoli, Bavaria was left defenceless once again.
The Swedes sent a second force under von Königsmarck to attack Prague, seizing the castle and Malá Strana district in July. The main objective was to gain as much loot as possible before the war ended; they failed to take the Old Town but captured the Imperial library and treasures including the Codex Gigas, which can now be seen in Stockholm. When a Spanish offensive in Flanders ended with defeat at Lens in August 1648, Ferdinand finally agreed terms and on 24 October, he signed peace treaties with France and Sweden, ending the war.

## Conflict outside Germany
### Northern Italy

Northern Italy had been contested by France and the Habsburgs since the end of the 15th century, as its control provided access to the vulnerable southern borders of France and Austria. In addition, large sections of the Spanish Road ran through it, a route that allowed Spain to safely move recruits and supplies from their Italian possessions to support their war against the Dutch. This reliance on long exterior lines of communication was a strategic weakness, which the French sought to exploit by disrupting the Road. This usually involved attacks on the Spanish-held Duchy of Milan, or blocking the Alpine passes.
Montferrat and its fortress of Casale Monferrato were subsidiary territories of the Duchy of Mantua and their possession allowed the holder to threaten Milan. This meant when the last duke in the direct line died in December 1627, France and Spain backed rival claimants, resulting in the 1628 to 1631 War of the Mantuan Succession. The French-born Duke of Nevers was backed by France and the Republic of Venice, his rival the Duke of Guastalla by Spain, Ferdinand II, Savoy and Tuscany. While a relatively minor conflict, the struggle had a disproportionate impact on the Thirty Years War, since Pope Urban VIII viewed Habsburg expansion in Italy as a threat to the Papal States. His opposition to Ferdinand II divided the Catholic powers, and made it acceptable for France to employ Protestant allies against Austria.
In March 1629, the French stormed Savoyard positions in the Pas de Suse, lifted the Spanish siege of Casale, and captured Pinerolo. The Treaty of Suza then ceded the two fortresses to France and allowed their troops unrestricted passage through Savoyard territory, giving them control over Piedmont and the Alpine passes into southern France. However, as soon as the main French army withdrew in late 1629, the Spanish and Savoyards besieged Casale once again. At the same time, mercenaries funded by Ferdinand II were used in a Spanish offensive which routed the main Venetian field army, and forced Nevers to abandon Mantua. By October 1630, the French position seemed so precarious their representatives agreed the Treaty of Ratisbon. It was never ratified, as Richelieu claimed he had not approved the terms.
Several factors restored the French position in northern Italy, notably a devastating outbreak of plague; between 1629 and 1631, over 60,000 died in Milan and 46,000 in Venice, with proportionate losses elsewhere. Richelieu took advantage of the diversion of Imperial resources to fund a Swedish invasion of Germany, whose success forced the Spanish-Savoyard alliance to withdraw from Casale and sign the Treaty of Cherasco in April 1631. Nevers was confirmed as Duke of Mantua and although Richelieu's representative, Cardinal Mazarin, agreed to evacuate Pinerolo, it was later secretly returned under an agreement with Victor Amadeus I, Duke of Savoy. With the exception of the 1639 to 1642 Piedmontese Civil War, this secured the French position in northern Italy for the next twenty years.
After the outbreak of the Franco-Spanish War in 1635, Richelieu supported a renewed offensive by Victor Amadeus against Milan to tie down Spanish resources. These included an unsuccessful attack on Valenza in 1635, plus minor victories at Tornavento and Mombaldone. However, the anti-Habsburg alliance in northern Italy fell apart when first Charles of Mantua died in September 1637, then Victor Amadeus in October, whose death led to a struggle for control of the Savoyard state between his widow Christine of France and brothers, Thomas and Maurice.
In 1639, their quarrel erupted into open warfare, with France backing Christine and Spain the two brothers, and resulted in the Siege of Turin. One of the most famous military events of the 17th century, at one stage it featured no less than three different armies besieging each other. However, revolts in Portugal and Catalonia forced the Spanish to cease operations in Italy, and the war was settled on terms favourable to Christine and France.
In 1647, a French-backed rebellion succeeded in temporarily overthrowing Spanish rule in Naples. The Spanish quickly crushed the insurrection and restored their rule over all of southern Italy, defeating multiple French expeditionary forces sent to back the rebels. However, it exposed the weakness of Spanish rule in Italy and the alienation of the local elites from Madrid. In 1650, the governor of Milan wrote that as well as widespread dissatisfaction in the south, the only one of the Italian states that could be relied on was the Duchy of Parma.

### Catalonia

Throughout the 1630s, tax increases levied to pay for the war led to protests throughout Spanish territories, which in 1640 resulted in revolts: first in Portugal, then in the Principality of Catalonia. Backed by France as part of Richelieu's 'war by diversion', in January 1641 the rebels proclaimed a Catalan Republic. The Madrid government quickly assembled an army of 26,000 men to crush the revolt, which defeated the rebels at Martorell on 23 January 1641. The French now persuaded the Catalan Courts to recognise Louis XIII as Count of Barcelona, and ruler of Catalonia.
On 26 January, a combined French-Catalan force routed a larger Spanish army at Montjuïc and secured Barcelona. However, the rebels soon found the new French administration differed little from the old, turning the war into a three-sided contest between the Franco-Catalan elite, the rural peasantry, and the Spanish. There was little serious fighting after France took control of Perpignan and Roussillon, establishing the current-day Franco-Spanish border in the Pyrenees. The revolt ended in 1651 when Madrid recaptured Barcelona.

### Outside Europe

In 1580, Philip II of Spain also became ruler of the Portuguese Empire, creating the Iberian Union; long-standing commercial rivals, the 1602 to 1663 Dutch–Portuguese War was an offshoot of the Dutch fight for independence from Spain. The Portuguese dominated the trans-Atlantic economy known as the Triangular trade, in which slaves were transported from West Africa and Portuguese Angola to work on plantations in Portuguese Brazil, which exported sugar and tobacco to Europe. Known by Dutch historians as the 'Great Design", control of this trade would not only be extremely profitable but also deprive the Spanish of funds needed to finance their war in the Netherlands.
In 1621, the Dutch West India Company was formed to achieve this, and a Dutch fleet captured the Brazilian port of Salvador, Bahia in 1624. After it was retaken by the Portuguese in 1625, a second fleet established Dutch Brazil in 1630, which was not returned until 1654. In 1641, the Dutch seized Portuguese slave trading hubs in Angola and São Tomé, with support from the kingdoms of Kongo and Ndongo, whose position was threatened by Portuguese expansion. Although those gains proved short-lived, the Dutch retained territories elsewhere, like the Cape Colony, as well as Portuguese trading posts on the Gold Coast, in Malacca, on the Malabar Coast, the Moluccas and Ceylon.

## Peace of Westphalia (1648)

The final Peace of Westphalia consisted of three separate agreements. These were the Peace of Münster between Spain and the Dutch Republic, the Treaty of Osnabrück between the Empire and Sweden, and the Treaty of Münster between the Empire and France. Preliminary discussions began in 1642, with a total of 109 delegations attending talks at one time or other, split between Münster and Osnabrück. After the Swedes rejected Christian of Denmark as mediator, the negotiators finally agreed on Papal Legate Fabio Chigi, and Venetian envoy Alvise Contarini.
The first to be signed on 30 January 1648, the Peace of Münster forms part of the Westphalia settlement since the Dutch Republic was still considered Imperial territory. Despite confirming Dutch sovereignty, the Imperial Diet did not formally accept it was no longer part of the Empire until 1728. The Dutch also gained a monopoly over trade conducted through the Scheldt estuary, ensuring the commercial ascendancy of Amsterdam. Antwerp, capital of the Spanish Netherlands and previously the most important port in northern Europe, would not recover economically until the late 19th century.
The terms of the separate treaties with France and Sweden had first to be agreed by Ferdinand and the Imperial estates. It has been argued they were a "major turning point in German and European...legal history", because they went beyond normal peace settlements and effected major constitutional and religious changes to the Empire itself. These negotiations were complex, with states like Saxony and Bavaria having very different views on desired outcomes, while Ferdinand continued to hope for an improvement in his military position. With Swedish troops on the verge of taking Prague, he finally signed the Peace on 24 October.
Key elements of the Peace were provisions confirming the autonomy of states within the Empire, including Ferdinand's acceptance of the supremacy of the Imperial Diet, and those seeking to prevent future religious conflict. Article 5 reconfirmed the Augsburg settlement, established 1624 as the basis, or "Normaljahr", for determining the dominant religion of a state and guaranteed freedom of worship for religious minorities. Article 7 recognised Calvinism as a Reformed faith and removed the ius reformandi, the requirement that if a ruler changed his religion, his subjects had to follow suit. These terms did not apply to the hereditary lands of the Habsburg monarchy, such as Lower and Upper Austria.
In terms of territorial concessions, Brandenburg-Prussia received Farther Pomerania, and the bishoprics of Magdeburg, Halberstadt, Kammin, and Minden. Frederick's son Charles Louis regained the Lower Palatinate and became the eighth imperial elector, although Bavaria kept the Upper Palatinate and its electoral vote. Externally, Spain accepted Dutch independence, while Ferdinand confirmed that of the Swiss, effectively autonomous since 1499. In Lorraine, the Three Bishoprics of Metz, Toul and Verdun, occupied by France since 1552, were formally ceded, as were the cities of the Décapole in Alsace, with the exception of Strasbourg and Mulhouse. Sweden received an indemnity of five million thalers, the imperial territories of Swedish Pomerania, and the Prince-bishoprics of Bremen and Verden, which also gave them a seat in the Imperial Diet.
The Peace was denounced by Pope Innocent X, who regarded the bishoprics ceded to France and Brandenburg as property of the Catholic church, and thus his to assign. It also disappointed many exiles by accepting Catholicism as the dominant religion in Bohemia, Upper and Lower Austria, all Protestant strongholds prior to 1618. Fighting did not end immediately, since demobilising over 200,000 soldiers took time, and the last Swedish garrison did not leave Germany until 1654. In addition, Mazarin insisted on excluding the Burgundian Circle from the Treaty of Münster, allowing France to continue its campaign against Spain in the Low Countries, a war that continued until the 1659 Treaty of the Pyrenees. The political disintegration of Poland-Lithuania led to the 1655 to 1660 Second Northern War with Sweden, which also involved Denmark, Russia and Brandenburg, while two Swedish attempts to impose its control on the port of Bremen failed in 1654 and 1666.
It has been argued the Peace established the principle known as Westphalian sovereignty, the idea of non-interference in domestic affairs by outside powers, although this has since been challenged. The 'Congress' model was used for peace negotiations at Aix-la-Chapelle in 1668, Nijmegen in 1678, and Ryswick in 1697, although unlike the 19th century 'Congress' system, these were intended to end wars, rather than prevent them.

## Human and financial cost of the war

The Thirty Years' War is part of what historians sometimes call "The General Crisis" of the mid-17th century, a period of sustained conflict and unrest in areas ranging from Ming China to the British Isles, Tsarist Russia and the Holy Roman Empire. In each of these, fighting combined with famine and disease to inflict severe losses on local civilian populations. While the war certainly ranks as one of the worst of these events, 19th century German nationalists often exaggerated its impact to illustrate the dangers of a divided Germany.
Claims of up to 12 million deaths from a population of 18 million are no longer considered realistic, while upper estimates of material losses are not supported by contemporary evidence, or in some cases exceed prewar tax records. Regardless, modern commentators agree the war was a man-made mortality disaster previously unknown in Europe. Estimates of total deaths range from 4.5 to 8 million, most incurred after 1630 when Sweden entered the war, the vast majority being civilians.
Battles generally featured armies of around 13,000 to 20,000 each, one of the largest being Alte Veste in 1632 with a combined 70,000 to 85,000. Estimates of the total deployed by both sides within Germany range from an average of 80,000 to 100,000 from 1618 to 1626, peaking at 250,000 in 1632 and falling to under 160,000 by 1648.
Casualty rates for those who served in the military could be extremely high. Of 230 men conscripted from the Swedish village of Bygdeå between 1621 and 1639, 215 are recorded as dead or missing, while another 5 returned home crippled. Historian Peter Wilson puts those killed or wounded in action at around 450,000. Research shows disease increased that number by a factor of between two and three, which suggests total military casualties ranged from 1.3 to 1.8 million. Sociologist Pitirim Sorokin calculates an upper limit of 2,071,000 military casualties, although his methodology has been disputed.
Local returns show only 3% of civilian deaths were caused by military action, the major causes being starvation (12%), bubonic plague (64%), typhus (4%), and dysentery (5%). Poor harvests throughout the 1630s and repeated plundering of the same areas led to widespread famine, with reports of people eating grass, too weak to accept alms, or resorting to cannibalism. Although regular outbreaks of disease were common prior to 1618, their spread was accelerated by the influx of foreign soldiers, the shifting locations of battle fronts, and displacement of rural populations into already crowded cities. Soldiers transferred from Germany allegedly sparked the 1629–1631 Italian plague, described as the "worst mortality crisis to affect Italy during the early modern period". This resulted in some 280,000 deaths, with estimates of up to a million.
Modern historians generally agree the Holy Roman Empire experienced an overall population decline from 18 and 20 million in 1600, to between 11 and 13 million in 1650, and did not regain pre-war levels until 1750. Nearly 50% of these losses were incurred during the first period of Swedish intervention from 1630 to 1635. The high mortality rate was partly due to the reliance of all sides on foreign mercenaries, often unpaid and required to live off the land. Lack of a sense of 'shared community' resulted in atrocities such as the destruction of Magdeburg, in turn creating large numbers of refugees who were extremely susceptible to sickness and hunger. While flight saved lives in the short-term, in the long run it often proved catastrophic.
In 1940, agrarian historian Günther Franz published an analysis of data from across Germany covering the period from 1618 to 1648. Broadly confirmed by more recent work, he concluded about 40% of the civilian rural population became casualties, and 33% of the urban. These figures need to be read with care, since Franz calculated the absolute decline in pre and post-war populations, or 'total demographic loss'. They therefore include factors unrelated to death or disease, such as permanent migration to areas outside the Empire or lower birthrates, a common but less obvious impact of extended warfare. There were also wide regional variations, with areas of northwest Germany experiencing minimal loss of population, while those of Mecklenburg, Pomerania and Württemberg fell by nearly 50%.
Although some towns may have overstated their losses to avoid taxes, individual records confirm serious declines; from 1620 to 1650, the population of Munich fell from 22,000 to 17,000, that of Augsburg from 48,000 to 21,000. The financial impact is less clear; while the war caused short-term economic dislocation, especially in the period 1618 to 1623, overall it accelerated existing changes in trading patterns. It does not appear to have reversed ongoing macro-economic trends, such as the reduction of price differentials between regional markets, and a greater degree of market integration across Europe. The death toll may have improved living standards for the survivors; one study shows wages in Germany increased by 40% in real terms between 1603 and 1652.

## Military developments

Innovations made by Gustavus in particular are considered part of the evolution known as the "Military Revolution", although whether tactics or technology were at the heart of these changes is still debated. Introduced by Maurice of Orange in the 1590s, these sought to increase infantry firepower by moving from massed columns to line formation. Gustavus further reduced the ten ranks used by Maurice to six, and increased the proportion of musketeers to pikemen. He also enhanced their firepower by providing each unit with quick-firing light artillery pieces on either flank. The best example of their application in battle was the victory over Tilly's traditionally organised army at Breitenfeld in September 1631.
Line formations were often harder to co-ordinate, as demonstrated when the supposedly obsolete Spanish tercios defeated the Swedes at Nördlingen in 1634. Since they also lacked the offensive impact of columns, Gustavus compensated by requiring his cavalry to be far more aggressive, often employing Finnish Hakkapeliitta as shock troops. However, even the Swedes used columns on occasion, notably the failed assault at Alte Veste in September 1632. The line versus column debate continued into the early 19th century, and both were employed during the Napoleonic Wars.
Such tactics needed professional soldiers, who could retain formation, reload and fire disciplined salvos while under attack, as well as the use of standardised weapons. The first half of the 17th century saw the publication of numerous instruction manuals showing the movements required, thirty-two for pikemen and forty-two for musketeers. In theory, it took up to six months to train infantry to operate in this way, but in reality many went into battle with far less experience. It also placed greater responsibility on junior officers who provided the vital links between senior commanders and the tactical unit. One of the first military schools designed to produce such men was set up at Siegen in 1616, and others soon followed.
On the other hand, strategic thinking failed to develop at the same pace. Historian Jeremy Black claims most campaigns were "inconclusive", since they were primarily concerned with gaining access to supplies and money for the soldiers, rather than focused strategic objectives. The disconnect between military and diplomatic goals helps explain why the war lasted so long, and peace proved so elusive. When fighting officially ended in 1648, there were still over 150,000 troops under arms within the Empire, small numbers by modern standards, but unprecedented at the time. Most 17th century states could not finance armies of this size for extended periods, forcing them to depend on "contributions" from areas they passed through.
Supplies thus became the limiting factor in planning campaigns, a problem that grew more acute as the war progressed. Armies became smaller, with a greater emphasis on cavalry that could cover greater distances and move faster, rather than slow moving infantry. Poor infrastructure also required commanders to stay close to rivers, then the primary means of bulk transportation, and meant they could not move too far from their main bases. Feeding the troops became an objective in itself, unconnected to diplomatic goals and largely uncontrolled by their central governments. The result was "armies increasingly devoid of intelligible political objectives...degenerating into travelling armed mobs, living in a symbiotic relationship with the countryside they passed through". This often conflicted with the political aims of their employers; the devastation inflicted in 1628 and 1629 by Imperial troops on Brandenburg and Saxony, both nominally allies, was a major factor in their support for Swedish intervention.
Finally, some commentators argue that while the Thirty Years War certainly played its part in accelerating new tactics and technology, of greater significance was the need to fund, supply and direct permanent armies over long periods of time and across wide ranging theatres. This required much more sophisticated mechanisms, and led to the transfer of organised violence from "contractor" generals like Wallenstein or Mansfeld to nation states. In that sense, the truly "revolutionary" aspect of the so-called Military Revolution was less on the tactics or technology used by soldiers, but the institutions required to support them.

## Social and cultural impact

It has been suggested the breakdown of social order caused by the war was often more significant and longer lasting than the immediate damage. The collapse of local government created landless peasants, who banded together to protect themselves from the soldiers of both sides, and led to widespread rebellions in Upper Austria, Bavaria and Brandenburg. Soldiers devastated one area before moving on, leaving large tracts of land empty of people and changing the ecosystem. Food shortages were worsened by an explosion in the rodent population, while Bavaria was overrun by wolves in the winter of 1638, and its crops destroyed by packs of wild pigs the following spring.
Contemporaries spoke of a "frenzy of despair" as people sought to make sense of the relentless and often random bloodshed unleashed by the war. Attributed by religious authorities to divine retribution, attempts to identify a supernatural cause led to a series of witch-hunts, starting in Franconia in 1626, then quickly spreading to other parts of Germany. They began in the Bishopric of Würzburg, an area with a history of such events going back to 1616 and now re-ignited by Bishop von Ehrenberg, a devout Catholic eager to assert the church's authority in his territories. By the time he died in 1631, over 900 people from all levels of society had been executed.
The Bamberg witch trials, held in the nearby Bishopric of Bamberg from 1626 to 1631, claimed over one thousand lives; in 1629, 274 died in the Eichstätt witch trials, plus another 50 in the adjacent Duchy of Palatinate-Neuburg. Elsewhere, persecution followed Imperial military success, expanding into Baden and the Palatinate following their reconquest by Tilly, then into the Rhineland. However, the extent to which they were symptomatic of the impact of the conflict on society is debatable, since many took place in areas relatively untouched by the war. Concerned their brutality would discredit the Counter-Reformation, Ferdinand ensured active persecution largely ended by 1630.
Although the war caused immense destruction, it has also been credited with sparking a revival in German literature, including the creation of societies dedicated to "purging foreign elements" from the German language. One example is Simplicius Simplicissimus, often suggested as one of the earliest examples of the picaresque novel; written by Hans Jakob Christoffel von Grimmelshausen in 1668, it includes a realistic portrayal of a soldier's life based on his own experiences, many of which are verified by other sources. Other less famous examples include the diaries of Peter Hagendorf, a participant in the Sack of Magdeburg whose descriptions of the everyday brutalities of the war remain compelling.
For German, and to a lesser extent Czech writers, the war was remembered as a defining moment of national trauma, the 18th century poet and playwright Friedrich Schiller being one of many to use it in their work. Variously known as the 'Great German War,' 'Great War' or 'Great Schism', for 19th and early 20th century German nationalists it showed the dangers of a divided Germany and was used to justify the creation of the German Empire in 1871, as well as the Greater Germanic Reich envisaged by the Nazis. Bertolt Brecht used it as the backdrop for his 1939 anti-war play Mother Courage and Her Children, while its enduring cultural resonance is illustrated by the novel Tyll; written by Austro-German author Daniel Kehlmann and also set during the war, it was nominated for the 2020 Booker Prize.

## Political consequences

The Peace reconfirmed "German liberties", ending Habsburg attempts to convert the Holy Roman Empire into a centralised state similar to Spain. Over the next 50 years, Bavaria, Brandenburg-Prussia, Saxony and others increasingly pursued their own policies, while Sweden gained a permanent foothold in the Empire. Despite these setbacks, the Habsburg lands suffered less from the war than many others. They also became a far more coherent geographical bloc with the addition of Bohemia, and the restoration of Catholicism throughout their territories.
By laying the foundations of the modern nation state, Westphalia changed the relationship between rulers and ruled, many of whom previously had multiple political and religious allegiances. After 1648, they were now understood to be subject first and foremost to the laws and edicts of their respective state authority, not the claims of any other entity, either religious or secular. This made it easier to levy national forces loyal to the state and its leader; one lesson learned from Wallenstein and the Swedish invasion was the need for their own permanent armies, and German society became far more militarised.
For Sweden, the benefits ultimately proved short-lived. Unlike French gains, which were incorporated into France, Swedish territories remained part of the Empire, and they became members of the Lower and Upper Saxon kreis. While this provided both seats and influence in the Imperial Diet, it also brought Sweden into direct conflict with Brandenburg-Prussia and Saxony, their competitors in Pomerania. The income from their German possessions was relatively minor, and although parts of Pomerania remained Swedish until 1815, much of it was ceded to Prussia in 1679 and 1720.
France arguably gained more from the conflict than any other power, and by 1648, most of Richelieu's objectives had been achieved. These included separation of the Spanish and Austrian Habsburgs, expansion of the French frontier into the Empire, and an end to Spanish military supremacy in northern Europe. Although the Franco-Spanish war continued until 1659, Westphalia allowed Louis XIV to begin replacing Spain as the predominant European power.
While religion remained a divisive political issue in many countries, the Thirty Years' War is arguably the last major European conflict where it was a primary driver. Future religious conflicts were either internal, such as the Camisards revolt in southern France, or relatively minor, like the 1712 Toggenburg War. The war created the outlines of a Europe that persisted until 1815 and beyond, most significantly the nation-state of France, along with the start of a split between Germany and a separate Austro-Hungarian bloc.