Opolian Silesia

Opole Silesia or Opolian Silesia, is a loosely defined historical region of Poland, part of Upper Silesia.
Throughout much of its history, the region was ruled by the Duchy of Opole and other Silesian duchies, formed during the medieval fragmentation of Piast-ruled Poland. Following the Silesian Wars, the region became part of Prussia, and from 1871 to 1945 it was incorporated into Germany. After Germany's defeat in World War II, in accordance with the Oder–Neisse line, Opole Silesia was reintegrated into Poland.