According to Gallus Anonymus the young prince was poisoned during a feast on orders of palatine Sieciech (who as Gallus Anonymus wrote wanted to "kill off the entire Piast dynasty") in Cracow in 1089.
Menurut Gall Anonim, sang pangeran muda diracuni di dalam pesta perjamuan atas perintah palatinus Sieciech (seperti yang dituliskan Gall Anonim ingin "membunuh seluruh anggota keluarga Wangsa Piast") di Kraków tahun 1089.