The Italian War of 1542–1546 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 peaking in Ceresole and concluding with Serravalle. Charles and Henry invaded France in turn, but the long sieges 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 foundation 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 King Francis of France and King Henry VIII of England, in early 1547 left the resolution of the Italian Wars to their successors.
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 Guelders 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, Charles was in Mallorca, 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 King Francis's eldest son, the Dauphin Henri, 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 schismatic, 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, 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; the French defenders of the town, commanded by Martin du Bellay, repulsed the Imperial attack, but Francis withdrew to Saint-Quentin on 4 November, leaving the Emperor free to march north and seize Cambrai.