Bolesław Jerzy II of Mazovia (b. 1308)
Yuri II Boleslav (Ukrainian: Юрій-Болеслав Тройденович Yuri Boleslav Troydenovich; Polish: Bolesław Jerzy II; c. 1305/1310 – April 7, 1340), was King of Ruthenia and Dominus of the lands of Galicia–Volhynia (1325-1340). A foreigner and a Catholic by birth, he was the son of Trojden I, Duke of Masovia and a member of the Polish Piast dynasty. Highly unpopular in Orthodox Ruthenia, his murder prompted a war of succession, known as the Galicia–Volhynia Wars.