He is described in the Wielkopolska Chronicle, written in the 14th century, where he is said to have taken power in Poland after the death of his father Mieszko II, as he was the eldest son.
Ia digambarkan di Tarikh Wielkopolska, yang ditulis pada abad ke-14, di mana ia dikatakan telah berkuasa di Polandia setelah kematian ayahandanya Mieszko II, karena ia adalah putra sulung.