When the baron supported a Savoy invasion of the Ossola south of Valais the leaders of the movement became increasingly concerned.

The Barons of Raron allied with, first the Duke of Savoy and then Bern, while the three Zenden of the Upper Valais entered into a treaty with Lucerne, Uri and Unterwalden.

[3] Lucerne, Uri and Unterwalden were reluctant to directly oppose Bern, instead, they chose to invade the Ossola valley.

They were successful in reaching a temporary compromise, but after Valais troops attacked and besieged Raron castles, Bern invaded over the Sanetsch Pass and plundered Sion in 1418.

However, in September 1419 near the village of Ulrichen a force of 400[1] to 600[2] under the leadership of Thomas Brantschen ambushed and fought the Bernese army to a standstill.

[2] The Valais rebels were now isolated and had lost many of their homes while Bern had suffered heavy losses from a small force at Ulrichen.

With his authority damaged, his castles burned and a sullen population, the Baron abandoned Valais and died in Rome in 1431.