Herzogtum Oppeln
After the death of Mieszko's grandson Duke Władysław Opolski in 1281, his sons again divided the Duchy of Opole and Racibórz and the Duchy of Opole was recreated for Casimir and his brother Bolko I, contemporaneously with the establishment of the duchies of Cziesyn and Bytom on former Racibórz territory. In 1327 King John the Blind of Bohemia reasserted his influence over the Duchy of Opole in an attempt to stabilise the situation.