He is depicted in historiography as the main responsible party for the Murder of Veer, the mass execution of 62 men of the garrison of Greifensee Castle after their surrender, on 28 May 1444.
He succeeded in greatly expanding the territory of Schwyz by consent of king Sigismund, acquiring jurisdiction over Einsiedeln, March, and Küssnacht.
Zürich reacted with a trade embargo, forcing Schwyz to import wheat from Aargau and the Alsace.
Zürich then made a defensive pact with the House of Habsburg, effectively reneging their membership in the Swiss Confederacy.
In modern historiography, Theodor von Liebenau (1870) based on letters written by eye witnesses concluded that the decision to execute the garrison had been taken by consensus of the commanders of all cantons present (Schwyz, Uri, Unterwalden, Glarus, Bern, Lucerne, Zug).