 During the time of the transalpine campaigns of the Old Swiss Confederacy from the early 15th century onwards, Chiavenna was controlled by the Three Leagues' forces, fighting against the Sforza who had succeeded the Visconti as Dukes of Milan.In 1486 they set Chiavenna ablaze; two years later, Ludovico Sforza had the town fortified.Nevertheless, Chiavenna was conquered by the Leagues's forces during the War of the League of Cambrai, when they allied with the Swiss Confederacy defeating the French troops of King Louis XII at the 1513 Battle of Novara.