It was the decisive battle in the southern Grisons of the Swabian War; after the defeat of the Habsburg troops, the king had to abandon his attempts to control the Engadin and the Val Müstair.

Since the early Middle Ages, the Bishopric of Chur and the Counts of Tyrol had been disputing and quarrelling over the judicial rights in the lower Engadin, the Val Müstair, and the Vinschgau.

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.

The bishop's reeve in the southern Grisons, Benedikt Fontana, was forced to leave his seat on the Fürstenburg at Burgeis in the Vinschgau.

Castle Rotund at Taufers in front of the barrier was also manned with Habsburg troops, and 200 men guarded the bridge at Marengo behind the Letzi.

The mats, as the soldiers of the Three Leagues were called in Romansh,[5] decided to split at Müstair: about 2,000 – 3,000 men led by Wilhelm Ringk and Hans von Lombris were to march over the mountains to bypass the Letzi on the north and to attack the enemy from behind.

When they arrived in the morning in the Vinschgau, they were immediately engaged by Habsburg troops, who fled in panic, however, when rumours that they numbered 30,000 made the round.

But the defense was strong; the Letzi was equipped with many cannons, and the mats were driven back several times and suffered heavy losses.

The victorious troops of the Three Leagues pillaged the Vinschgau valley for three days, burning every house and killing all men over twelve years of age.

Legend has it that he cheered on his men to attack the Habsburg fortifications with the words "Hei fraischgiamank meiss matts, cun mai ais be ün hom da fear, quai brichia guardad, u chia hoatz Grischuns e Ligias u maa non plü!