His nickname of Kantner was derived from the town of Kanth (pl: Kąty Wrocławskie), who was a property of the Oleśnica dukes since 1379.

On 4 April 1431 they raided Gliwice, which was occupied by the Hussites and where just held religious discussions in which the Lithuanian prince Sigismund Korybut, a nephew of Vytautas, was involved.

Their fight against the Hussites was rewarded by Emperor Sigismund, who, in his capacity as King of Bohemia, in 1434 transfer to them the districts of Psie Pole and Psary.

Three years later, in 1437 he confirmed to them the complete investiture of this territories by Escheat, so that upon the death of the childless Konrad VII they could reverted to the Kingdom.

His sons were excluded from the government by their uncle Konrad VII, who maintained his rule until 1450, when they finally deposed him and assumed the full control over the Duchy.