At the end of the 9th century Silesia came within the sphere of influence of two neighbours, the Holy Roman Empire and Poland. In 971, in order to proselytise Silesia to Christianity, Holy Roman emperor Otto I donated the tithe of the Dziadoszyce area to the Diocese of Meissen, and in 996 Otto III defined the Oder up to the spring as the border of the Margraviate of Meissen. This was without practical consequences as the expanding Polish state of Mieszko I conquered Silesia at the same time. The Dziadoszyce area was already incorporated . In 990 in the Polish-Bohemian War Mieszko annexed Middle Silesia and its main township Niemcza with the help of the Holy Roman Empire, which supported Poland in order to weaken Bohemia. Mieszko's successor, Bolesław I established an independent Polish ecclesiastical province in 1000 (see: Congress of Gniezno) the bishopric of Wrocław, subordinate to the archbishopric of Gniezno.