Mieszko I of Poland mentions a gift or dedication of Mieszko's land to the Pope (the act took place almost a hundred years earlier). It is roughly his borders that Poland was returned to in 1945. There is no certain information on Mieszko I's life before he took control over his lands. Only the "Lesser Poland Chronicle" gives the date of his birth as somewhere between the years 920–931 (depending on the version of the manuscript), however, modern researchers don't recognize the Chronicle as a reliable source. Several historians on the basis of their investigations postulated the date of Mieszko I's birth to have
Mieszko II Lambert to Hungary because during his travel he was stopped by Rus' troops. King Stephen I of Hungary wasn't favorable to accepting him in his country. Without alternatives, Mieszko II went to Bohemia. Duke Oldřich once again imprisoned him. This time the King wasn't counting with the Imperial support. Mieszko II was not only imprisoned but also castrated, which was to be a punishment to Bolesław I the Brave, who blinded Duke Boleslaus III the Red (Oldřich's brother) thirty years before. Mieszko II and his wife never reunited again; according to some sources they were either officially divorced or only separated.