ボレスワフ4世
The progenitor of the Piława Clan was supposed to have been Żyrosław z Potoka, who was fighting the Prussians, a pagan tribe and brought himself glory in the Battle of Piława, where he fought along Bolesław IV the Curly. The legend states that Żyrosław reached the pagan chief, fought him in hand-to-hand combat and killed him. The terrified enemy hordes fled the battle field. The related legend tells also that in 1166, to commemorate the victory, Bolesław IV bestowed a coat of arms upon Żyrosław, naming it for the place, where the battle took place.