History of Poland during the Piast dynasty of Lesser Poland, the country of the Vistulans, and of Silesia (both taken by Mieszko from the Czech state during the later part of the 10th century), Mieszko's state reached its mature form, including the main regions regarded as ethnically Polish. The Piast lands totaled about in area, with an approximate population of under one million. Initially a pagan, Mieszko I was the first ruler of the Polans tribal union known from contemporary written sources. A detailed account of aspects of Mieszko's early reign was given by Ibrâhîm ibn Ya`qûb, a Jewish traveler, according to whom Mieszko was one of
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