sentences:  With the death of Casimir's grandson Duke Bolesław in 1355 the Bytom branch of the Piasts became extinct and in the following inheritance dispute his widow Margareta of Sternberg had to cede the northern part of the duchy including the lordship of Koźle to Duke Konrad I of Oleśnica, while the remaining part was bequested to Duke Casimir I of Cieszyn.Bytom remained divided until in 1459 Duke Wenceslaus I of Cieszyn sold his portion to Duke Konrad IX the Black of Oleśnica and the duchy was reunited under his rule.In 1472 Matthias Corvinus of Hungary, then self-declared King of Bohemia, annexed Bytom and pledged it to Lord Jan of Zierotin.