In what year did Sigismund Casimir's mother die?
Cecilia Renata of Austria Archduchess Cecilia Renata of Austria (German: "Cäcilia Renata"; Polish: "Cecylia Renata"; 16 July 1611 – 24 March 1644) was Queen of Poland as consort to the Polish-Lithuanian Commonwealth's King Władysław IV Vasa.
Hedwig of Sagan Hedwig of Sagan (Polish: "Jadwiga żagańska" ; before 1350 – 27 March 1390) was Queen of Poland as the fourth wife of Casimir III. Casimir's lack of male heir spelled the end of the Piast Dynasty in the Kingdom of Poland. After Casimir's death in 1370, she remarried Rupert I of Legnica.