Casimir of Bytom Duke of Opole and Bytom (1250–1312) Parents Euphemia of Greater Poland Vladislaus I of Opole Children George of Bytom Siemowit of Bytom Mieszko of Bytom Maria of Bytom Władysław of Bytom Bolesław of Toszek Siblings Przemysław of Racibórz Constance, Duchess of Wodzisław Mieszko I, Duke of Cieszyn Bolko I of Opole Partners Helena