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 which culminated in the bloody Battle of Ceresole. Charles and Henry then proceeded to invade France, 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 Francis and Henry in early 1547 left the resolution of the Italian Wars to their successors.
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 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.