Casimir I of Cieszyn, was Duke of Cieszyn from 1315, Duke of Siewierz from 1337 and Duke of Bytom from 1357.
He was the second son of Mieszko I, Duke of Cieszyn by his wife, probably called Grzymisława. Wikipedia
Born: 1280
Died: September 29, 1358 (age 78 years)
Children: Przemyslaus I Noszak, Duke of Cieszyn, Elisabeth of Cieszyn, Agnes of Cieszyn, and more
Grandchildren: Bolesław I, Duke of Cieszyn, Konrad III the Old, Rupert I of Legnica, and more
Grandparents: Vladislaus I of Opole and Euphemia of Greater Poland
Great grandchildren: Casimir I of Oświęcim, Bolesław II, Duke of Cieszyn, Wenceslaus I, Duke of Cieszyn, and more
Great-grandparents: Casimir I of Opole, Władysław Odonic, and Viola, Duchess of Opole