After the Swiss defeat at the Battle of Marignano in 1515, the three villages again declared their allegiance to the Duchy of Milano, but the Three Leagues refused to recognize this and sent an occupying force. In Perpetual Peace of 1516 between France and Switzerland, the villages were not named so that their "de jure" affiliation remained uncertain, and the king of France (as duke of Milan) demanded that the Three Leagues return the villages to Milan. The Milanese steward of Musso occupied Sorico and Gravedona, resulting in the armed conflict known as "Müsserkrieg". The Three Leagues were forced to abandon their claim on the territory in 1526, and it remained part of the Duchy of Milan during the Early Modern period.