波列斯瓦夫一世
Bolesław's life is also described in a text written by Wincenty z Kielczy (13th century) and some other sources. In the "Annals of Kraków" under the date of 1038 was placed the information about a "king Bolesław's" death. This date cannot be connected with Bolesław I Chrobry (who died in 1025) and Bolesław II the Bold (dead in 1081, deposed and exiled) so it may refer to the Forgotten. In addition, an indirect reference to his existence may be found in the "Małopolska Chronicle", where Bolesław III Wrymouth is called Bolesław IV. Also, in the "Tyniec Codec" (destroyed in the 19th century), Bolesław II the Generous was given the Roman numeral III. This gives some grounds to believe that between Bolesław I Chrobry and Bolesław II could be placed another Bolesław.