1,500 Tyrolian soldiers on the Roya mountain The Battle of Frastanz between an army of the Old Swiss Confederacy and the troops of King Maximilian I of the Holy Roman Empire took place on 20 April 1499.

In one of the many raids of the Swabian War, an expedition of Habsburg troops had plundered some villages in the Swiss Confederacy, who responded by sending an army to Vorarlberg.

At Frastanz, a few kilometers south-east of Feldkirch, the Habsburg troops had blocked the entry to the Montafon valley with a strong wooden fortification called a Letzi.

Many Landsknechte drowned in the river Ill. Because a frontal assault on the strong fortifications at Frastanz seemed futile, the commander of the Swiss troops, Heinrich Wolleb from Uri, devised an alternate battle plan.

Some 2,000 men were to cross the Roya mountain, clear it from Tyrolean troops, and then attack the main camp of the Habsburg army from the side.