Question: What is the date of death of Casimir Ii Of Belz's mother?
Sentence (from "Casimir II of Belz"): He was a Duke of Płock, Rawa Mazowiecka, Gostynin, Sochaczew, Belz, Płońsk, Zawkrze and Wizna during 1426–1434 jointly with his brothers, and after the division of the paternal inheritance between him and his brothers in 1434, sole ruler over Belz.
Relevant evidence: No