In order to curb the increasing power of Habsburgs and their interest in Grisons, municipalities in Engadine, Bergün, Oberhalbstein and Chur created the Gotteshausbund, which was followed in 1424 by the Graue or Obere Bund (the area around the Vorderrhein and Hinterrhein) and the Zehngerichtebund (eleven municipalities in northern Grisons).
At the time of the Schwabenkrieg (1499) between the Eidgenossen and the Habsburgers, Emperor Maximilian (1469-1519) invaded Engadine to conquer the Münstertal and the passes, among others the Umbrail Pass. That led to the battle at Calven (Chalavaina in Romansh) on 22 May 1499, where the army commander Benedikt Fontana would have distinguished himself by leading his troops to victory.
Maximilian lost not only this battle but the Schwabenkrieg, which ended the political and military power of Habsburg in Switzerland. The Eidgenossenschaft was to expand to 13 members in 1513. (Source: T. Cavadini Canonica, A. Canonica, Das Engadin. Kurze Geschichte einer Alpinen Welt, Sondrio 2009).