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 in the entry for the year 985 it is noted that Mieszko came to help the Saxons in their fight against some Slavic forces, presumably the Polabians. One year later, the Polish ruler had a personal meeting with the Emperor, an event mentioned in the "Annals of Hersfeld": According to Thietmar and other contemporary chronicles the gift given by Mieszko to the Emperor was a camel. The meeting consolidated the Polish-German alliance, with Mieszko joining Otto's expedition against a Slavic land, which "together they wholly devastated (...) with fire and tremendous depopulation". It is not clear which Slavic territory was