At the beginning of the 16th century Swiss mercenaries were the most feared in Europe, and for a few years the Confederates controlled the Duchy of Milan. On 13 and 14 September 1515, at Marignano, today's Melegnano, the army of Francis I defeated them in one of the bloodiest battles of the century.
With the «Perpetual Peace» of 1516 the Confederates gave up Milan but kept the lands south of the Alps that would form Ticino. From then on they abandoned wars of conquest: for many historians this is where the Swiss tradition of neutrality was born.