Henry II in 1239 had to resign the regency of Upper Silesia in favour of his cousin Mieszko II the Fat. He anew defended Lubusz, this time against the forces of the Ascanian margraves of Brandenburg, and in 1241 granted it to his second son Mieszko. The hopes for a re-unification of the Polish lands under the Silesian Piasts ended with the Mongol invasion of Poland and Henry's death at the 1241 Battle of Legnica. His eldest son Bolesław II the Bald could not prevail as High Duke against Bolesław V the Chaste of Lesser Poland and, after he regained Lubusz upon the death of his brother Mieszko in 1242, finally had to divide his Silesian heritage with his younger brothers in 1248: