In what year did Sigismund Casimir's mother die?
Sigismund Casimir Sigismund Casimir, Crown Prince of Poland (Polish: "Zygmunt Kazimierz Waza" ), (1 April 1640 – 9 August 1647) - was the only legitimate son of King Władysław IV and his first wife Queen Cecilia Renata. He was named after his grandfather Sigismund III, and uncle John Casimir.
Maria Christina of Habsburg Maria Christierna of Austria (10 November 1574 – 6 April 1621), was a Princess of Transylvania by marriage to Sigismund Báthory, and for a period in 1598 elected sovereign Princess regnant of Transylvania.