Italian War of 1542 – 46 The Italian War of 1542 – 46 was a conflict late in the Italian Wars , pitting Francis I of France and Suleiman I of the Ottoman Empire against the Holy Roman Emperor Charles V and Henry VIII of England . The course of the war saw extensive fighting in Italy , France , and the Low Countries , as well as attempted invasions of Spain and England . The conflict was inconclusive and ruinously expensive for the major participants . The war arose from the failure of the Truce of Nice , which ended the Italian War of 1536 – 1538 , to resolve the long - standing conflict between Charles and Francis — particularly their conflicting claims to the Duchy of Milan . Having found a suitable pretext , Francis once again declared war against his perpetual enemy in 1542 . Fighting began at once throughout the Low Countries ; the following year saw the Franco - Ottoman alliance ' s attack on Nice , as well as a series of maneuvers in northern Italy which culminated in the bloody Battle of Ceresole . Charles and Henry then proceeded to invade France , but the long siege s of Boulogne - sur - Mer and Saint - Dizier prevented a decisive offensive against the French . Charles came to terms with Francis by the Treaty of Crépy in late 1544 , but the death of Francis ' s younger son , the Duke of Orléans — whose proposed marriage to a relative of the Emperor was the cornerstone of the treaty — made it moot less than a year afterwards . Henry , left alone but unwilling to return Boulogne to the French , continued to fight until 1546 , when the Treaty of Ardres finally restored peace between France and England . The deaths of Francis and Henry in early 1547 left the resolution of the Italian Wars to their heirs . Prelude . The Truce of Nice , which ended the Italian War of 1536 – 1538 , provided little resolution to the long conflict between the Holy Roman Emperor and the King of France ; although hostilities had ended , giving way to a cautious entente , neither monarch was satisfied with the war ' s outcome . Francis continued to harbor a desire for the Duchy of Milan , to which he held a dynastic claim ; Charles , for his part , insisted that Francis comply at last with the terms of the Treaty of Madrid , which had been forced on the French king during his captivity in Spain after the Italian War of 1521 – 26 . Other conflicting claims to various territories — Charles ' s to Burgundy and Francis ' s to Naples and Flanders , among others — remained a matter of contention as well . Negotiations between the two powers continued through 1538 and into 1539 . In 1539 , Francis invited Charles — who faced a rebellion in the Low Countries — to travel through France on his way north from Spain . Charles accepted , and was richly received ; but while he was willing to discuss religious matters with his host — the Protestant Reformation being underway — he delayed on the question of political differences , and nothing had been decided by the time he left French territory . In March 1540 , Charles proposed to settle the matter by having Maria of Spain marry Francis ' s younger son , the Duke of Orléans ; the two would then inherit the Netherlands , Burgundy , and Charolais after the Emperor ' s death . Francis , meanwhile , was to renounce his claims to the duchies of Milan and Savoy , ratify the treaties of Madrid and Cambrai , and join an alliance with Charles . Francis , considering the loss of Milan too large a price to pay for future possession of the Netherlands and unwilling to ratify the treaties in any case , made his own offer ; on 24 April , he agreed to surrender the Milanese claim in exchange for immediate receipt of the Netherlands . The negotiations continued for weeks , but made no progress , and were abandoned in June 1540 . Francis soon began gathering new allies to his cause . William , Duke of Jülich - Cleves - Berg , who was engaged in the Guelderian Wars , a dispute with Charles over the succession in Guelders , sealed his alliance with Francis by marrying Francis ' s niece , Jeanne d ' Albret . Francis sought an alliance with the Schmalkaldic League as well , but the League demurred ; by 1542 , the remaining potential French allies in northern Germany had reached their own understandings with the Emperor . French efforts farther east were more fruitful , leading to a renewed Franco - Ottoman alliance ; Suleiman the Magnificent of the Ottoman Empire , seeking to distract Charles from Ottoman advances in Hungary , encouraged the Franco - Imperial rift . On 4 July 1541 , however , the French ambassador to the Ottoman court , Antoine de Rincon , was killed by Imperial troops as he was travelling near Pavia . In response to Francis ' s protests , Charles denied all responsibility , promising to conduct an inquiry with the assistance of the Pope ; he had by now formed plans for a campaign in North Africa , and wished to avoid further entanglements in Europe . By the end of September 1541 , Charles was in Majorca , preparing an attack on Algiers ; Francis , considering it impolitic to attack a fellow Christian who was fighting the Muslims , promised not to declare war for as long as the Emperor was campaigning . The Imperial expedition , however , was entirely unsuccessful ; storms scattered the invasion fleet soon after the initial landing , and Charles had returned to Spain with the remainder of his troops by November . On 8 March 1542 , the new French ambassador , Antoine Escalin des Eymars , returned from Constantinople with promises of Ottoman aid in a war against Charles . Francis declared war on 12 July , naming various injuries as the causes ; among them was Rincon ' s murder , which he proclaimed " an injury so great , so detestable and so strange to those who bear the title and quality of prince that it cannot be in any way forgiven , suffered or endured " . Initial moves and the Treaty of Venlo . The French immediately launched a two - front offensive against Charles . In the north , the Duke of Orléans attacked Luxembourg , briefly capturing the city ; in the south , a larger army under Claude d ' Annebault and Francis ' s eldest son , the Dauphin Henry , unsuccessfully besieged the city of Perpignan in northern Spain . Francis himself was meanwhile in La Rochelle , dealing with a revolt caused by popular discontent with a proposed reform of the " gabelle " tax . By this point , relations between Francis and Henry VIII were collapsing . Henry — already angered by the French refusal to pay the various pensions , which were owed to him under the terms of past treaties — was now faced with the potential of French interference in Scotland , where he was entangled in the midst of an attempt to marry his son to Mary , Queen of Scots , that would develop into the open warfare of the " Rough Wooing " . He had intended to begin a war against Francis in the summer of 1543 , but negotiating a treaty to that effect with the Emperor proved difficult ; since Henry was , in Charles ' s eyes , a schism atic , the Emperor could not promise to defend him against attack , nor sign any treaty which referred to him as the head of the Church — both points upon which Henry insisted . Negotiations continued for weeks ; finally , on 11 February 1543 , Henry and Charles signed a treaty of offensive alliance , pledging to invade France within two years . In May 1543 , Henry sent Francis an ultimatum threatening war within twenty days ; and , on 22 June , at last declared war . Hostilities now flared up across northern France . On Henry ' s orders , Sir John Wallop crossed the Channel to Calais with an army of 5 , 000 men , to be used in the defense of the Low Countries . The French , under Antoine de Bourbon , Duke of Vendôme , had captured Lillers in April ; by June , d ' Annebault had taken Landrecies as well . Wilhelm of Cleves openly joined the war on Francis ' s side , invading Brabant , and fighting began in Artois and Hainaut . Francis inexplicably halted with his army near Rheims ; in the meantime , Charles attacked Wilhelm of Cleves , invading the Duchy of Jülich and capturing Düren . Concerned about the fate of his ally , Francis ordered the Duke of Orléans and d ' Annebault to attack Luxembourg , which they took on 10 September ; but it was too late for Wilhelm , as he had already surrendered on 7 September , signing the Treaty of Venlo with Charles . By the terms of this treaty , Wilhelm was to concede the overlordship of the Duchy of Guelders and County of Zutphen to Charles , and to assist him in suppressing the Reformation . Charles now advanced to besiege Landrecies , seeking battle with Francis ; but , after a brief standoff , Francis withdrew to Saint - Quentin on 4 November , leaving the Emperor free to march north and seize Cambrai . Nice and Lombardy . On the Mediterranean , meanwhile , other engagements were underway . In April 1543 , the Sultan had placed Hayreddin Barbarossa ' s fleet at the disposal of the French king . Barbarossa left the Dardanelles with more than a hundred galley s , raided his way up the Italian coast , and in July arrived in Marseilles , where he was welcomed by François de Bourbon , Count of Enghien , the commander of the French fleet . On 6 August , the joint Franco - Ottoman fleet anchored off the Imperial city of Nice and landed troops at Villefranche ; a siege of the city followed . Nice fell on 22 August , although the citadel held out until the siege was lifted on 8 September . Barbarossa was by this point becoming a liability ; on 6 September , he had threatened to depart if he were not given the means with which to resupply his fleet . In response , Francis ordered that the population of Toulon — except for " heads of households " — be expelled , and that the city then be given to Barbarossa , who used it as a base for his army of 30 , 000 for the next eight months . Yet Francis , increasingly embarrassed by the Ottoman presence , was unwilling to help Barbarossa recapture Tunis ; so the Ottoman fleet — accompanied by five French galleys under Antoine Escalin des Aimars — sailed for Istanbul in May 1544 , pillaging the Neapolitan coast along the way . In Piedmont , meanwhile , a stalemate had developed between the French , under the Sieur de Boutières , and the Imperial army , under Alfonso d ' Avalos ; d ' Avalos had captured the fortress of Carignano , and the French had besieged it , hoping to force the Imperial army into a decisive battle . During the winter of 1543 – 44 , Francis significantly reinforced his army , placing Enghien in command . D ' Avalos , also heavily reinforced , advanced to relieve Carignano ; and , on 11 April 1544 , Enghien and d ' Avalos fought one of the few pitched battles of the period at Ceresole . Although the French were victorious , the impending invasion of France itself by Charles and Henry forced Francis to recall much of his army from Piedmont , leaving Enghien without the troops he needed to take Milan . D ' Avalos ' s victory over an Italian mercenary army in French service at the Battle of Serravalle in early June 1544 brought significant campaigning in Italy to an end . France invaded . On 31 December 1543 , Henry and Charles had signed a treaty pledging to invade France in person by 20 June 1544 ; each was to provide an army of no less than 35 , 000 infantry and 7 , 000 cavalry for the venture . Against this Francis could muster about 70 , 000 men in his various armies . The campaign could not begin , however , until Henry and Charles had resolved their personal conflicts with Scotland and the German princes , respectively . On 15 May , Henry was informed by the Edward Seymour , Earl of Hertford , that , after his raids , Scotland was no longer in a position to threaten him ; he then began to make preparations for a personal campaign in France — against the advice of his council and the Emperor , who believed that his presence would be a hindrance . Charles had meanwhile reached an understanding with the princes at the Diet of Speyer , and the Electors of Saxony and Brandenburg had agreed to join his invasion of France . By May 1544 , two Imperial armies were massed to invade France : one , under Ferrante Gonzaga , Viceroy of Sicily , north of Luxemburg ; the other , under Charles himself , in the Palatinate . On 25 May , Gonzaga captured Luxembourg and moved towards Commercy and Ligny , issuing a proclamation that the Emperor had come to overthrow " a tyrant allied to the Turks " . On 8 July , Gonzaga besieged Saint - Dizier ; Charles and the second Imperial army soon joined him . Henry , meanwhile , had sent an army of some 40 , 000 men to Calais under the joint command of Thomas Howard , Duke of Norfolk , and Charles Brandon , Duke of Suffolk . While Henry continued to squabble with the Emperor over the goals of the campaign and his own presence in France , this massive army moved slowly and aimlessly into French territory . Finally , Henry decided that the army was to be split . Norfolk , ordered to besiege Ardres or Montreuil , advanced towards the latter ; but he proved unable to mount an effective siege , complaining of inadequate supplies and poor organization . Suffolk was ordered to attack Boulogne ; on 14 July , Henry crossed to Calais and moved to join him . A siege of Boulogne began on 19 July — despite the protests of the Emperor , who insisted that Henry should advance towards Paris . Charles himself , on the other hand , was still delayed at Saint - Dizier ; the city , fortified by Girolamo Marini and defended by Louis IV de Bueil , Count of Sancerre , continued to hold out against the massive Imperial army . On 24 July , Charles captured Vitry - le - François , from which French forces had harassed his supply lines ; finally , on 8 August , the defenders of Saint - Dizier , running low on supplies , sought terms . On 17 August , the French capitulated , and were permitted by the Emperor to leave the city with banners flying ; their resistance for 41 days had broken the Imperial offensive . Some of Charles ' s advisers suggested withdrawing , but he was unwilling to lose face and continued to move towards Châlons , although the Imperial army was prevented from advancing across the Marne by a French force waiting at Jâlons . The Imperial troops marched rapidly through Champagne , capturing Épernay , Châtillon - sur - Marne , Château - Thierry , and Soissons . The French made no attempts to intercept Charles . Troops under Jacques de Montgomery , Sieur de Lorges , sacked Lagny - sur - Marne , whose citizens had allegedly rebelled ; but no attempt was made to engage the advancing Imperial army . Paris was gripped by panic , although Francis insisted that the population had nothing to fear . Charles finally halted his advance and turned back on 11 September . Henry , meanwhile , was personally directing the besiegers at Boulogne ; the town fell in early September , and a breach was made into the castle on 11 September . The defenders finally surrendered a few days later . Treaty of Crépy . Charles , short on funds and needing to deal with increasing religious unrest in Germany , asked Henry to continue his invasion or to allow him to make a separate peace . By the time Henry had received the Emperor ' s letter , however , Charles had already concluded a treaty with Francis — the Peace of Crépy — which was signed by representatives of the monarchs at Crépy - en - Laonnais in Picardie on 18 September 1544 . The treaty had been promoted at the French court by the Emperor ' s sister , Queen Eleanor , and by Francis ' s mistress , the Duchess of Étampes . By its terms , Francis and Charles would each abandon their various conflicting claims and restore the " status quo " of 1538 ; the Emperor would relinquish his claim to the Duchy of Burgundy and the King of France would do the same for the Kingdom of Naples , as well as renouncing his claims as suzerain of Flanders and Artois . The Duke of Orléans would marry either Charles ' s daughter Mary or his niece Anna ; the choice was to be made by Charles . In the first case , the bride would receive the Netherlands and Franche - Comté as a dowry ; in the second , Milan . Francis , meanwhile , was to grant the duchies of Bourbon , Châtellerault , and Angoulême to his son ; he would also abandon his claims to the territories of the Duchy of Savoy , including Piedmont and Savoy itself . Finally , Francis would assist Charles against the Ottomans — but not , officially , against the heretics in his own domains . A second , secret accord was also signed ; by its terms , Francis would assist Charles with reforming the church , with calling a General Council , and with suppressing Protestantism — by force if necessary . The treaty was poorly received by the Dauphin , who felt that his brother was being favored over him , by Henry VIII , who believed that Charles had betrayed him , and also by the Sultan . Francis would fulfill some of the terms ; but the death of the Duke of Orléans in 1545 rendered the treaty moot . Boulogne and England . The conflict between Francis and Henry continued . The Dauphin ' s army advanced on Montreuil , forcing Norfolk to raise the siege ; Henry himself returned to England at the end of September 1544 , ordering Norfolk and Suffolk to defend Boulogne . The two dukes quickly disobeyed this order and withdrew the bulk of the English army to Calais , leaving some 4 , 000 men to defend the captured city . The English army , outnumbered , was now trapped in Calais ; the Dauphin , left unopposed , concentrated his efforts on besieging Boulogne . On 9 October , a French assault nearly captured the city , but was beaten back when the troops prematurely turned to looting . Peace talks were attempted at Calais without result ; Henry refused to consider returning Boulogne , and insisted that Francis abandon his support of the Scots . Charles , who had been appointed as a mediator between Francis and Henry , was meanwhile drawn into his own disputes with the English king . Francis now embarked on a more dramatic attempt to force Henry ' s hand — an attack on England itself . For this venture , an army of more than 30 , 000 men was assembled in Normandy , and a fleet of some 400 vessels prepared at Le Havre , all under the command of Claude d ' Annebault . On 31 May 1545 , a French expeditionary force landed in Scotland . In early July , the English under John Dudley , Viscount Lisle , mounted an attack on the French fleet , but had little success due to poor weather ; nevertheless , the French suffered from a string of accidents : d ' Annebault ' s first flagship burned , and his second ran aground . Finally leaving Le Havre on 16 July , the massive French fleet entered the Solent on 19 July and briefly engaged the English fleet , to no apparent effect ; the major casualty of the skirmish , the " Mary Rose " , sank accidentally . The French landed on the Isle of Wight on 21 July , and again at Seaford on 25 July , but these operations were abortive , and the French fleet soon returned to blockading Boulogne . D ' Annebault made a final sortie near Beachy Head on 15 August , but retired to port after a brief skirmish . Treaty of Ardres . By September 1545 , the war was a virtual stalemate ; both sides , running low on funds and troops , unsuccessfully sought help from the German Protestants . Henry , Francis , and Charles attempted extensive diplomatic maneuvering to break the deadlock ; but none of the three trusted the others , and this had little practical effect . In January 1546 , Henry sent the Earl of Hertford to Calais , apparently preparing for an offensive ; but one failed to materialize . Francis could not afford to resume a large - scale war , and Henry was concerned only for the disposition of Boulogne . Negotiations between the two resumed on 6 May . On 7 June 1546 , the Treaty of Ardres — also known as the Treaty of Camp — was signed by Claude d ' Annebault , Pierre Ramon , and Guillaume Bochetel on behalf of Francis , and Viscount Lisle , Baron Paget and Nicholas Wotton on behalf of Henry . By its terms , Henry would retain Boulogne until 1554 , then return it in exchange for two million écu s ; in the meantime , neither side would construct fortifications in the region , and Francis would resume payment of Henry ' s pensions . Upon hearing the price demanded for Boulogne , the Imperial ambassador told Henry that the city would remain in English hands permanently . During the treaty negotiations , two Protestant mediators — Han Bruno of Metz and Johannes Sturm — were concerned that Henry ' s war in Scotland was a stumbling block . The sixteenth article of the treaty made Scotland a party to the new peace , and Henry pledged not to attack the Scots again without cause . This gave Scotland a respite from the War of the Rough Wooing , but the fighting would recommence 18 months later . Aftermath . Exorbitantly expensive , the war was the costliest conflict of both Francis ' s and Henry ' s reigns . In England , the need for funds led to what Elton terms " an unprecedented burden of taxation " , as well as the systematic debasement of coinage . Francis also imposed a series of new taxes and instituted several financial reforms . He was not , therefore , in a position to assist the German Protestants , who were now engaged in the Schmalkaldic War against the Emperor ; by the time any French aid was to be forthcoming , Charles had already won his victory at the Battle of Mühlberg . As for Suleiman , the conclusion of the Truce of Adrianople in 1547 brought his own struggle against the Habsburgs to a temporary halt . Henry VIII died on 28 January 1547 ; on 31 March , Francis followed . Henry ' s successors continued his entanglements in Scotland . When , in 1548 , friction with the Scots led to the resumption of hostilities around Boulogne , they decided to avoid a two - front war by returning the city four years early , in 1550 . The causes of the war themselves — chiefly , the contested dynastic claims in Italy — remained unresolved until the Peace of Cateau - Cambrésis ended the Italian War of 1551 – 1559 and six decades of conflict .