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 I of Poland a child became a man. That explains that Mieszko wasn't blind in fact. He was blind only metaphorically. Besides his son's name was also Mieszko and it is hard to believe that he was also blind. In addition, as we know today ancient Slavs used only abstract names among nobility. The third theory links the name of Mieszko with his other name, Dagome, as it appeared in the document called "Dagome iudex". We know this document only from a copy prepared by an anonymous monk who was not familiar with Polish language or Polish names. It is possible that while