After World War I, the easternmost part of Upper Silesia was granted to Poland by the Entente Powers after insurrections by Poles and the Upper Silesian plebiscite. The remaining former Austrian parts of Silesia were partitioned to Czechoslovakia, forming part of Czechoslovakia's Sudetenland region, and are today part of the Czech Republic. In 1945, after World War II, most of Silesia was transferred to Polish jurisdiction by the Potsdam Agreement between the victorious Allies and became part of Poland, whose Communist government expelled most of Silesia's population. The small Lusatian strip west of the Oder–Neisse line, which had belonged to Silesia since 1815, remained in Germany.