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.
Anne of Austria, Queen of Poland Anne of Austria (16 August 1573 – 10 February 1598) was queen consort of Poland and Sweden by marriage to King Sigismund III Vasa.