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 II the Fat Mieszko II the Fat Mieszko II the Fat () ( – 22 October 1246) was a Duke of Opole-Racibórz from 1230 until his death, and Duke of Kalisz-Wieluń during 1234–1239 (with his brother as co-ruler). He was the eldest son of Duke Casimir I of Opole by his wife Viola, probably a Bulgarian lady. At the time of his father's death in 1230, Mieszko II and his younger brother Władysław were still minors; for this, the regency of the Duchy was taken by their mother and Henry I the Bearded, Duke of Wrocław. Following her late husband's politics, the Dowager