Herzogtum Glogau
In the late 10th century, the area was included in the emerging Polish state by its first historic ruler Mieszko I of the Piast dynasty. It became part of the Duchy of Silesia, a province of fragmented Poland, in 1138, and, later belonged to the Silesian Duchy of Głogów, established in 1249-51 under the rule of Duke Konrad I. In the beginning of the 14th century, Sulechów was encompassed by defensive walls.