ter, in 1340, Milan besieged Bellinzona. Following a lengthly siege, the city fell to Milan but the Ruscas were allowed to keep Montebello. Pro-papacy Milan would dominate Bellinzona for the next one and a half centuries, though the pro-Imperial Rusca would also occupy part of the city.
Expansion of Bellinzona under Milan
Under the control of the Visconti trade flourished and the city of Bellinzona grew. Even when an alternative route over the Alps, the Sch�llenen bridge opened, traffic in the St. Gotthard increased to the highest levels ever. During the second half of the 14th century a long wall, known as the Murata, was built across the entire Tessin valley. This wall allowed Milan to protect and tax the trade route over the St. Gotthard Pass. While the city was controlled by Milan through the Visconti after 1340, the Visconti did not have a formal title and feudal rights until 1396 when they were granted by King Wenceslaus. However, the orderly growth of Bellinzona was threatened in 1402 when Duke Gian Galeazzo Visconti died. In 1403 Bellinzona was taken under the control of Alberto di Sacco of Val Mesolcina. He held Bellinzona until 1419 when it was taken over by Uri and Obwalden which had expanded into the Leventina Valley. Milan attacked the city three years later in 1422 after an offer to buy the city was rejected by theSwiss Confederation. The troops from Uri and Obwalden were quickly driven from the city and later defeated at the Battle of Arbedo on 30 June 1422. This defeat discouraged the expansionist intentions of Uri and its allies towards Lake Maggiore for a time.
During the period of unrest following Gian Galeazzo Visconti's death, a tower which would become the nucleus of the third castle, Sasso Corbaro, was built outside the city.
While the border between Uri and Milan was fixed in the peace treaty of 1426, in 1439 Uri invaded again. While they were unable to take Bellinzona, the victories of the Swiss
