Opole (ôpôˈlĕ) [key], Ger. Oppeln, city (1992 est. pop. 129,000), capital of Opolskie prov., S Poland, on the Oder River. A river port and rail junction, it is also an important trade center, with manufactures of cement, metals, and furniture. Originally a Slavic settlement, it was the seat (1163–1532) of the dukes of Opole of the Piast dynasty. The duchy passed (1532) to the house of Hapsburg and (1742) to Prussia and was incorporated into Poland in 1945. It was the capital (1919–45) of the Prussian province of Upper Silesia. In the city are the churches of St. Adalbert (10th cent.) and of the Holy Cross (14th cent.).