The Italian War of 1494-98 was the first of the Italian Wars, fought between the Kingdom of France against the Kingdom of Naples, which was later joined by the Papal-led "League of Venice" (Venice, Spain, Milan, the Holy Roman Empire, Florence, Mantua, and England). The war saw France conquer Naples before being forced to retreat through central and northern Italy while under attack from a large coalition of enemies. The war was the first of many wars fought in the peninsula from 1494 to 1559.
In 1489, Pope Innocent VIII excommunicated King Ferdinand I of Naples due to his refusal to pay feudal dues to the Papal States, and he invited King Charles VIII of France to claim the throne of Naples for himself. Pope Innocent died in 1492, and Pope Alexander VI opposed French interference in Italy; however, King Charles had already made plans to conquer Naples for France. King Ferdinand II of Aragon promised not to intervene in exchange for free rein in Roussillon and Cerdagne in the Pyrenees. The death of King Ferdinand I in 1494 led to Charles VIII invading Italy, and he was initially supported by Ludovico Sforza, Duke of Milan. Charles invaded with 25,000 troops (including 8,000 Swiss mercenaries), and the French defeated a Neapolitan army at Rapallo in the lands of the Republic of Genoa on 5 September 1494 before the Franco-Milanese army conquered Mordano on 19 October 1494 and massacred its inhabitants. In mid-November 1494, King Charles' army approached Florence, and Piero de Medici was forced into exile and a republican government installed. Any city that attempted to fight against Charles had its walls and defenses blasted with huge cannon, and the populace was massacred by the French soldiers. The French carved its cruel way south after conquering several cities. In February 1495, Naples fell without resistance, and he appointed Gilbert, Count of Montpensier his viceroy.
However, Pope Alexander formed the "League of Venice" to oppose French expansion into Italy, and this alliance included European powers such as Spain, the Holy Roman Empire, and, after 1496, England, as well as Italian states such as the Duchy of Mantua, the Duchy of Milan, and the Republic of Venice. Sforza played a key role in creating the alliance, as he feared that Charles would next seek to press his claims to the Duchy of Milan. In July 1495, the two alliances fought each other to a draw at the Battle of Fornovo, and Charles' army would ultimately survive its withdrawal into France. Charles' death in April 1498 brought an end to the war, as he was unable to mount another invasion of Italy.