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.
Anna Catherine Constance Vasa Anna Catherine Constance Vasa of Poland (Polish: "Anna Katarzyna Konstancja Waza" ; 7 August 1619 in Warsaw – 8 October 1651 in Cologne) was a Polish princess, daughter of King Sigismund III Vasa and his second wife Constance of Austria.