Treaty of Stettin ( 1630 ) The Treaty of Stettin ( or " Fördraget i Stettin " ) or Alliance of Stettin ( ) was the legal framework for the occupation of the Duchy of Pomerania by the Swedish Empire during the Thirty Years ' War . Concluded on 25 August ( O . S . ) or 4 September 1630 ( N . S . ) , it was predated to 10 July ( O . S . ) or 20 July 1630 ( N . S . ) , the date of the Swedish landing . Sweden assumed military control , and used the Pomeranian bridgehead for campaigns into Central and Southern Germany . After the death of the last Pomeranian duke in 1637 , forces of the Holy Roman Empire invaded Pomerania to enforce Brandenburg ' s claims on succession , but they were defeated by Sweden in the ensuing battles . Some of the Pomeranian nobility had changed sides and supported Brandenburg . By the end of the war , the treaty was superseded by the Peace of Westphalia ( 1648 ) and the subsequent Treaty of Stettin ( 1653 ) , when Pomerania was partitioned into a western , Swedish part ( Western Pomerania , thenceforth Swedish Pomerania ) , and an eastern , Brandenburgian part ( Farther Pomerania , thenceforth the Brandenburg - Prussian Province of Pomerania ) . Background . Following the Capitulation of Franzburg in 1627 , the Duchy of Pomerania was occupied by forces of Ferdinand II , Holy Roman Emperor , under command of Albrecht von Wallenstein . The Swedish intervention in the Thirty Years ' War began with the active military support of Stralsund , a Pomeranian Hanseatic port which since the Battle of Stralsund successfully resisted imperial occupation with Danish and Swedish support . Sweden and Stralsund concluded an alliance scheduled for twenty years . The Danish campaigns in Pomerania and other parts of the Holy Roman Empire ended with the Battle of Wolgast in 1628 and the subsequent Treaty of Lübeck in 1629 . Except for Stralsund , all of Northern Germany was occupied by forces of the emperor and the Catholic League . In 1629 , the emperor initiated the Re - Catholization of these Protestant territories by issuing the Edict of Restitution . The Truce of Altmark ended the Polish – Swedish War ( 1626 – 1629 ) in September 1629 , releasing the military capacities needed for an invasion of the Holy Roman Empire . Plans of Gustavus Adolphus of Sweden for such an intervention were approved of by a Riksdag commission already in the winter of 1627 / 28 , approval by the Riksråd followed in January 1629 . On 26 June ( O . S . ) or 6 July ( N . S . ) 1630 , Gustavus Adolphus of Sweden with a fleet of 27 ships arrived at the island of Usedom and made landfall near Peenemünde with 13 , 000 troops ( 10 , 000 infantry and 3 , 000 cavalry on thirteen transport ships ) . The core of the invasion force consisted of trained peasants , recruited to the Swedish army following Gustavus Adolphus ' military reforms of 1623 . The western flank of the Swedish invasion force was cleared from Stralsund , which served as the basis for Swedish forces clearing Rügen and the adjacent mainland from 29 March until June 1630 . The officially stated Swedish motives were : The Swedish landing force faced Albrecht von Wallenstein ' s imperial occupation forces in Pomerania , commanded by Torquato Conti . Large parts of the imperial army were pinned down in Italy and unable to react . Wallenstein , who two years before had expelled the Danish landing forces at the same place was about to be dismissed . On 9 July , Swedish forces took Stettin ( now Szczecin ) , but throughout 1630 were content with establishing themselves in the Oder estuary . The treaty and amendments . The first draft of a Swedish - Pomeranian alliance , which the Pomeranian ducal councillors had worked out since 20 July 1630 ( N . S . ) , was rejected by Gustavus Adolphus of Sweden . A second draft was returned to the council together with a list of modifications Sweden insisted on . On 22 August ( N . S . ) , actual Swedish - Pomeranian negotiations started , which Gustavus Adolphus on 1 September ( N . S . ) joined in person . The final negotiations lasted from 2 – 4 September ( N . S . ) . The actual agreement was made on 25 August ( O . S . ) or 4 September ( N . S . ) , but pre - dated to 10 July ( O . S . ) or 20 July 1630 ( N . S . ) . The alliance was to be " eternal " . The treaty also included the alliance with Stralsund of 1628 , which was concluded when the town resisted the Capitulation of Franzburg and was thus besieged by Albrecht von Wallenstein ' s army . Subsequent treaties were the " Pomeranian Defense Constitution " of 30 August 1630 ( O . S . ) , and the " Quartering Order " of 1631 . The Swedish king and the high - ranking officers were given absolute control over the duchy ' s military affairs , while the political and ecclesial power remained with the dukes , nobles , and towns . The duchy ' s foreign affairs were to be within the responsibility of the Swedish crown . The amending treaties were necessary because the Pomeranian nobility had insisted on having the shift in military control of the duchy to Sweden separate from the Swedish - Pomeranian alliance . The Pomeranian contributions detailed in the treaties amounted to an annual 100 , 000 Taler s . Furthermore , Pomerania was obliged to supply four Swedish garrisons . The alliance . Implementation in Pomerania . When Bogislaw XIV , Duke of Pomerania had concluded the alliance , he immediately wrote a letter to Ferdinand II , Holy Roman Emperor , reading " This union is not directed against the majesty of the Emperor or the Empire , but is rather designed to maintain the constitution of the Empire in its ancient state of liberty and tranquillity , and to protect the religious and secular settlements against the ravagers and disturbers of the public peace , and thereby not only to leave intact the relationship which binds us , Bogislaw XIV [ . . . ] to His Imperial Roman Majesty [ . . . ] but also to preserve our lawful duty and obligations to the same . " Bogislaw XIV further blamed the " barbarities and cruelties of the Imperial soldiers " for leaving him no choice . Yet , Ferdinand II did not forgive Bogislaw XIV , and instead the imperial occupation forces in Pomerania were instructed to act even more harshly . As a consequence , raids were conducted frequently , buildings and villages were burned , and the population was tormented . The imperial atrocities became one argument for the Pomeranian population to support Sweden . Another argument was that in contrast to Pomerania , there was no serfdom in Sweden , and thus the Pomeranian peasants held a very positive view of the Swedish soldiers , who were in fact peasants in arms . With the aforementioned treaties , Sweden included the Pomeranian duchy in her military contributions ' system , enabling her to triple the size of her forces there within a short period . In 1630 , Carl Banér was appointed Swedish legate in Stettin , succeeded in 1631 by Steno or Sten Svantesson Bielke , who in 1630 was the Swedish commander in Stralsund . From the Oder estuary bridgehead , the Swedish forces subsequently cleared the Duchy of Pomerania of imperial forces in 1631 . The Pomeranian towns of Gartz ( Oder ) and Greifenhagen ( now Gryfino ) , both south of Stettin , were attacked on 4 and 5 January 1631 . The imperial occupation forces had established a defense in both towns since 4 and 7 June 1630 . With these taken , Sweden was able to advance further south into Brandenburg , and west into Western Pomerania and Mecklenburg . The last imperial stronghold in Pomerania was Greifswald , which was besieged by Sweden since 12 June 1631 . When imperial commander Perusi was shot during a ride , the imperial garrison surrendered on 16 June . Gustavus Adolphus of Sweden even returned from Brandenburg to supervise the siege , and upon his arrival received the university ' s homage for the liberation . Support for Sweden among the peasants did not fade even when they were mobilized and recruited for military construction works . A different situation emerged in the towns , where burghers were often in conflict with the garrison . While the Swedish king issued several decrees ruling and restricting the interaction of soldiers and burghers , this did not prevent " turmoils against the undisciplined soldatesca " already in 1632 . The larger towns often refused to fulfill the demands of the Swedish military . Bridgehead for the Swedish intervention in the Holy Roman Empire . When Gustavus Adolphus landed in Pomerania , the German Protestant nobility met his intervention with distrust . In April 1631 , at a convention in Leipzig , they decided to set up a third front on their own , and except for Magdeburg , who had allied with Sweden already on 1 August 1630 , did not side with Sweden . In Swedish strategy , Magdeburg was to be the spark inflaming a " universal rebellion in Germany " - yet initially this strategy failed . In early 1631 , Swedish forces advanced into Brandenburgian territory . On 23 January 1631 , Sweden concluded an alliance with France in Brandenburgian Bärwalde ( now Mieszkowice ) near Greiffenhagen . Brandenburgian Frankfurt ( Oder ) and Landsberg ( Warthe ) ( now Gorzow ) were taken on 15 and 23 April , respectively . Subsequently , Brandenburg was forced into treaties with Sweden on 14 May , 20 June and 10 September 1631 . While these obliged George William , Elector of Brandenburg to hand over control of the Brandenburgian military to Sweden , he refused to enter an alliance . Sweden was not able to support Magdeburg , and in the summer of 1631 , the town was taken and looted by Johann Tserclaes , Count of Tilly ' s forces . When a fire destroyed what was left of the town , and 20 , 000 inhabitants were burned , the Protestants ' scepsis turned into support for the Swedish king . When Tilly attacked the Electorate of Saxony , the Saxon electors joined their forces with the Swedish army , and the combined forces decisively defeated Tilly in the Battle of Breitenfeld ( 1631 ) . This defeat of the combined imperial and Catholic League forces allowed Sweden to pursue deep into Central and Southern Germany . After Gustavus Adolphus ' death . Gustavus Adolphus was killed in the Battle of Lützen on 6 November 1632 . George William , Elector of Brandenburg , joined the obsequies in Stettin on 31 May , and proposed joining the Alliance of Stettin if he would in turn participate in the Pomeranian succession . Bogislaw XIV , Duke of Pomerania , the last living member of the House of Pomerania , had suffered a stroke already in April 1631 . Sweden neither approved nor rejected the Brandenburgian offer . On 19 November 1634 , a " regiment constitution " reformed the administration of the duchy of Pomerania . The two governments in Wolgast and Stettin resulting from the partition of 1569 had already been merged on 18 March . The new constitution reformed this government to consist of a proconsul , a president , and seven members . After Sweden had to acknowledge her first serious defeat in the Battle of Nördlingen ( 1634 ) , Ferdinand II , Holy Roman Emperor and several Protestant states concluded the Peace of Prague in May 1635 . Calvinist Brandenburg was reluctant to sign , since besides the announced annulment of the Edict of Restitution , toleration of Calvinism was not mentioned . To get Brandenburg to sign up , Sweden and Ferdinand promised her the succession in the Duchy of Pomerania in return . Another consequence of the lost Battle of Nördlingen was that large parts of the Swedish army , including thousands of injured , retreated to Pomerania , followed by imperial forces who entered the duchy in 1636 . The rigsråd considered to abandon all of Pomerania except for Stralsund . Both the atrocities committed by the Swedish soldiers and the contributions paid by Pomerania for the military peaked during the following years . Short of supplies , the Swedish as well as the imperial mercenaries forced their means of subsistence from the local population . In 1637 , a capitulation was issued that mentions " irruption " and " insolentia " by the military , and ruled out more drastic consequences for irregular behaviour of the soldiers . On 24 February 1637 , the Pomeranian councillors decided that the Pomeranian constitution of 1634 should remain in effect in case of the duke ' s death , which was approved of by Sweden and rejected by Brandenburg . After Bogislaw XIV ' s death - Confrontation with Brandenburg . On 10 March 1637 , Bogislaw XIV died without issue . Swedish legate Sten Svantesson Bielke on 11 March advised the Pomeranian council to nevertheless adhere to the Alliance of Stettin , and to reject any Brandenburgian interference . George William , Elector of Brandenburg , in turn mailed Christina of Sweden on 14 March to respect his succession in the Pomeranian duchy based on the treaties of Pyritz ( 1493 ) and Grimnitz ( 1529 ) , on which the alliance did not have any impact . Similar letters addressed Bielke , and Swedish field - marshal Carl Gustaf Wrangel . The same day , a courier arrived in Stettin with the elector ' s seizure patent , who at once was incarcerated by Bielke and threatened with death by hanging . The next day , the Brandenburgian elector admonished the Pomeranian nobility to behave as his subjects . On 19 March 1637 , a delegation of Pomeranian nobles pledged that the elector suspend his claims until a Swedish - Brandenburgian agreement was reached . The elector rejected , and Bielke on 24 March rejected any negotiations with Brandenburg . While Bielke clarified on 3 April , that he does not " per se " challenge the Brandenburgian claim , but rather Brandenburg ' s disregard of Swedish claims , Wrangel on 12 April definitely rejected any Brandenburgian claim and advised the Pomeranian nobility to remain loyal to Sweden . George William reacted on 28 April , repeating his claims of 14 March and threatening with imperial intervention . Ferdinand II issued a patent confirming the Brandenburgian succession , and George William issued another patent on 22 May . The Pomeranians assembled a Landtag between 7 and 29 June , where Bielke and the nobility agreed on resisting the pending Brandenburgian take - over . In August 1637 , an imperial army commanded by Matthias Gallas moved toward the Pomeranian frontier with Mecklenburg , and Swedish forces were concentrated on the Pomeranian side . While Gallas withdrew in late October , imperial forces commanded by von Bredow crossed into Western Pomerania on 24 / 25 October taking Tribsees , Loitz , Wolgast and Demmin . The nobles of the duchy ' s southern districts changed allegiance and rendered homage to the elector of Brandenburg on 25 November , and several nobles from the eastern districts Stolp and Schlawe met with the elector ' s ambassador in Danzig and obtained permission to resettle to East Prussia on 1 January 1638 . The same month , emperor Ferdinand II gave the duchy of Pomerania to Brandenburg as a fief , which was accepted by the nobility on 26 January . The Pomeranian government resigned in March . On 3 April 1638 , the Swedish rigsråd debates the Pomeranian issue , and decides to take over the duchy . On 2 May , Axel Lillje and Johann Lilljehök were appointed Swedish governors of Pomerania , occupied primarily with military tasks , and several other functionaries were appointed to administrate the duchy . Johan Nicodemi Lilleström was appointed to draft a schedule for the final integration of Pomerania into the Swedish Empire . On 28 July 1638 , Swedish field marshal Johan Banér from Farther Pomerania attacked the imperial forces in Western Pomerania . The ensuing warfare devastated the duchy . By the end of the year , Banér was appointed general governor of the whole duchy . Though Brandenburg prepared a military re - capture throughout 1639 - 1641 , she made no actual progress . Neither did attempts of Sweden and the Pomeranian nobility to re - establish a civilian government succeed . On 14 July 1641 , Sweden and Brandenburg agreed on a truce . Yet negotiations in February 1642 and April 1643 did not result in a settlement . Between 1 and 7 September 1643 , imperial forces commanded by von Krockow invaded the Duchy of Pomerania and took western Farther Pomerania . Swedish forces commanded by Hans Christoff von Königsmarck attacked Krockow on 1 October , the battles lasted until 12 November when Krockow retreated pursued by Königsmarck ' s forces . Aftermath . When peace talks started in Osnabrück to end the Thirty Years ' War , a Pomeranian delegation was present in early 1644 and from October 1645 to August 1647 . Stralsund had sent her own delegates , and the rest of the duchy was represented by von Eickstedt and Runge , accredited by both Sweden and Brandenburg . On 3 August , George William of Brandenburg ' s delegation started to negotiate a partition of the duchy with Sweden . While the Pomeranian nobility in October rejected a partition and urged Brandenburg to look for alternatives , the partition was made definite on 28 January 1647 in Osnabrück , signed as Peace of Westphalia on 24 October 1648 : Western Pomerania was to remain with Sweden , while Farther Pomerania was to become a fief of Brandenburg . Swedish field - marshal Carl Gustaf Wrangel was appointed general governor of Pomerania in 1648 . After the peace treaty , Sweden demobilized her forces in Pomerania , keeping between 2 , 000 and 4 , 000 troops . Swedish - Brandenburgian negotiations about the definite frontier started in early 1650 , resulting in another Treaty of Stettin which defined the exact border on 4 May 1653 . Bogislaw XIV was finally buried in Stettin on 25 May 1654 .