Euphrosyne of Masovia

Euphrosyne of Masovia also known as Eufrozja (1292–1328/1329) was Duchess of Oświęcim by her marriage. Euphrosyne was the daughter of Boleslaus II of Masovia, Prince of Plock and his second wife Kunigunde, daughter of Ottokar II of Bohemia. The genesis of her name is unknown. This is the first and the last time that princess of Masovian lineage of Piast was named Eufrozyna. Modern Polish historians usually named her Eufrozyna, but in sources she was mentioned mostly as Eufrazja. Her younger brother was Prince Wenceslaus of Płock (–1336). According to older historians Euphrosyne had also sister Berta, but she was a midget from Euphrosyne's mother court. Eufrozyna had also siblings from previous father's marriage. They were Siemowit II, Trojden I and wife of Władysław Prince of Leginca (her name is unknown). The date of birth of Euphrosyne is unknown. Her parents married in 1291, so she could be born not earlier than in 1292. According to genealogist Oswald Balzer Euphrosyne was born in 1292. This theory was based on fact that she must be at least 14 years old, when she get married in 1306 (her son Jan I was born in 1307).