Italian War of 1542–46: A French army defeats Habsburg forces at the Battle of Ceresole, but fails to exploit its victory.

The Italian War of 1542–46 was one of the later phases of the long Italian Wars, a series of conflicts fought primarily over control of territories in Italy and broader dominance in Europe. It began when Francis I of France renewed his struggle against Charles V, Holy Roman Emperor, whose power stretched across Spain, the Holy Roman Empire, and much of Italy. The immediate cause of the war was the unresolved rivalry over the Duchy of Milan, which both rulers considered strategically and politically vital. Francis also secured support from the Ottoman Empire under Suleiman the Magnificent, making this conflict notable for the Franco-Ottoman alliance against the Habsburgs.

The war was fought across several fronts, including northern Italy, southern France, the Low Countries, and the Mediterranean. One of its most famous engagements was the Battle of Ceresole (1544), where French forces won an impressive battlefield victory in Piedmont. At the same time, Ottoman naval forces under Hayreddin Barbarossa cooperated with France in the Mediterranean, most notably in the siege of Nice in 1543. Meanwhile, Charles V and Henry VIII of England launched invasions of France, with English troops capturing Boulogne in 1544. Despite several dramatic campaigns and costly sieges, neither side was able to secure a decisive strategic advantage, and the war gradually settled into an expensive stalemate.

The conflict formally ended through two major treaties: the Treaty of Crépy (1544) between Charles V and Francis I, and the Treaty of Ardres (1546) between France and England. Although the war ended without a clear victor, it had major consequences. It drained the finances of all participating states, deepened the rivalry between France and the Habsburgs, and further demonstrated the growing importance of international alliances in Renaissance warfare. The struggle over Italy remained unresolved, and within only a few years, hostilities resumed in the Italian War of 1551–59, continuing the broader contest for European supremacy.