Border disputes involving the ill-defined Swiss-Italian frontier…

Border disputes involving the ill-defined Swiss-Italian frontier increase with the number of traders and mercenaries crossing the St. Gotthard Pass.

The Swiss Confederation is attempting to expand into the southern foothills of the Alps to gain control of both ends of the valuable mountain passes.

In November 1478, Uri troops move south over the Gotthard pass into the Levantina valley.

The population of the valley, who have long been opposed to Milan, greet the Swiss troops as liberators and allies.

However, below the valley at Bellinzona, they find the city gates closed.

Uri is quickly joined by forces from other Confederation cantons and establishes a siege camp below the walls of Bellinzona on November 30, 1478.

Ludovico Sforza, acting as regent to the young Duke of Milan, Gian Galeazzo Sforza, responds by sending ten thousand men toward Bellinzona to drive the Confederates back and reassert his control over the Val Levantina.