Alexandra of Lithuania

Alexandra (, ; died 20 April 1434 in Płock) was the youngest daughter of Algirdas, Grand Duke of Lithuania, and his second wife, Uliana of Tver. Though Alexandra's exact date of birth is not known, it is thought that she was born in the late 1360s or early 1370s. In 1387, she married Siemowit IV, Duke of Masovia, and they had thirteen children. Life On 12 December 1385, few months after the Union of Krewo, Siemowit IV, Duke of Masovia, reached a compromise with king Jadwiga of Poland and her intended consort king Jogaila (Władysław II Jagiełło), brother of Alexandra. Siemowit IV agreed to cease his rival claims to the Kingdom of Poland, pay homage to Jadwiga and Jogaila, and to assume position of a hereditary vassal to the Polish Crown in exchange for 10,000 Prague groschen and fief Duchy of Belz. The agreement was solidified by marriage of Siemowit IV and Alexandra in 1387. Alexandra died and was buried in Płock. Her final resting place is likely a church of the Dominican Order. Issue In her union with Siemowit, Alexandra bore 13 children—five sons and eight daughters.