Mieszko I of Poland result of the conflict Silesia was taken over by Poland. However, the annexation of Silesia possibly took place around 985, because during this year the major Piast strongholds in Wrocław, Opole and Głogów were already being built. The issue of the incorporation of Lesser Poland is also not completely resolved. Possibly Mieszko took the region before 990, which is indicated by the vague remark of Thietmar, who wrote of a country taken by Mieszko from Boleslav. In light of this theory, the conquest of Lesser Poland could be a reason for the war, or its first stage. Many historians suggested
Mieszko I of Poland been between 922–945; the activity of the Duke in his final years of life puts the date of his birth closer to the latter year. There are three major theories concerning the origin and meaning of Mieszko I's name. The most popular theory, proposed by Jan Długosz, explains that Mieszko is a diminutive of "Mieczysław", a combination of two elements or lexemes: "Miecz" meaning sword and "Sław" meaning famous. Today, this theory is rejected by the majority of Polish historians, who consider the name Mieczysław to have been invented by Długosz to explain the origin of the name Mieszko. Today,