Leszek I the White
From a young age, Bolesław I became part of the ambitious political projects of his father. In 1227, after the assassination of the High Duke of Poland Leszek I the White, he accompanied his father to Lesser Poland to participate in negotiations on the succession with his widow Grzymisława. In view of the failure of the talks, Bolesław I received from his father the stronghold of Dobrzyń nad Wisłą until 1229, when Konrad I finally forced Grzymisława to surrender to Bolesław I a part of the Duchy of Sandomierz, the district of Radom. Immediately, Bolesław gave Dobrzyń nad Wisłą to his youngest brother, Siemowit I.