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.
Judith of Poland Judith of Poland (Polish: Judyta Bolesławówna , Hungarian: Judit lengyel hercegnő , German: Judith von Polen ; b. 1130/35 – died 8 July 1171/75), was a Polish princess member of the House of Piast and by marriage Margravine of Brandenburg.