 Until April 1499, a large Habsburg army with troops from the Swabian League, from Tyrol, and mercenaries from Italy assembled at the villages of Mals and Glurns in the Vinschgau.At Calven, they erected strongly armed wooden fortifications (a so-called "Letzi") blocking the entire exit of the Val Müstair.Habsburg troops tried to conquer the Pass dal Fuorn on May 11, 1499, but failed.