In 1152 King Conrad III died and was succeeded by his nephew Frederick Barbarossa. With this, the hopes of Władysław of returning to Poland were reborn. Following the inducements of Władysław and Frederick's aunt Agnes of Babenberg, the Holy Roman Emperor launched a new expedition to Greater Poland in 1157. The campaign was a success, but unexpectedly Frederick Barbarossa did not restore Władysław to the Polish throne, after Bolesław IV apprehended at Krzyszkowo had to declare himself a vassal to the Emperor and was compelled to pay tribute to him. In compensation, the Emperor forced Bolesław IV to promise the restitution of Silesia to Władysław's sons Bolesław the Tall and Mieszko IV Tanglefoot.