Prince Aleksander Janusz Zasławski-Ostrogski was the last male representative of the Ostrogski princely line. He was the 4th ordynat of the Ostrogski Family Fee Tail. Wikipedia
Born: March 6, 1650
Died: May 31, 1673 (age 23 years)
Aunt: Anna Rozalia Sobieska
Grandparents: Aleksander Zasławski, Jakub Sobieski, Teofila Zofia Sobieska, and more
Great-grandparents: Janusz Ostrogski, Janusz Zasławski, Jan Daniłowicz, and more
Parents: Władysław Dominik Zasławski and Katarzyna Sobieska