The territory became a part of the emerging Polish state under its first historic ruler Mieszko I in the 10th century. In the Middle Ages, Sobienie was granted to Bishops of Poznań. It was mentioned as a possession of the bishops in the confirmation of old privileges by Duke Bolesław II of Masovia in 1297, and Duke Siemowit III in 1351.[1]
^ abSłownik geograficzny Królestwa Polskiego i innych krajów słowiańskich, Tom X (in Polish). Warsaw. 1889. p. 944.{{cite book}}: CS1 maint: location missing publisher (link)