The Swiss mercenaries were a powerful infantry force constituted by professional soldiers originating from the cantons of the Old Swiss Confederacy. They were notable for their service in foreign armies, especially among the military forces of the kings of France, throughout the early modern period of European history, from the Late Middle Ages into the Renaissance. Their service as mercenaries was at its peak during the Renaissance, when their proven battlefield capabilities made them sought-after mercenary troops. There followed a period of decline, as technological and organizational advances counteracted the Swiss' advantages. Switzerland's military isolationism largely put an end to organized mercenary activity; the principal remnant of the practice is the Pontifical Swiss Guard at the Vatican.

The Burgundian Wars (1474–1477) were a conflict between the Burgundian State and the Old Swiss Confederacy and its allies. Open war broke out in 1474, and the Duke of Burgundy, Charles the Bold, was defeated three times on the battlefield in the following years and was killed at the Battle of Nancy in 1477. The Duchy of Burgundy and several other Burgundian lands then became part of France, and the Burgundian Netherlands and Franche-Comté were inherited by Charles's daughter, Mary of Burgundy, and eventually passed to the House of Habsburg upon her death because of her marriage to Maximilian I, Holy Roman Emperor.