Boleslaus II, c.1039–1081, duke (1058–76), and later king (1076–79) of Poland; son and successor of Casimir I. Throughout his reign he opposed the influence of the Holy Roman Empire. He asserted Polish power in Bohemia, Hungary, and S Russia by interfering in their civil wars. As a reward for submitting his foreign policy to papal control he was crowned king in 1076. He became involved in a sharp conflict with the Polish clergy and nobility, and in 1079 he killed (or procured the death of) Stanislaus, bishop of Kraków. The death provoked immediate reaction; the king's younger brother, Ladislaus Herman, joined in league with the powerful nobles and seized the royal power. Excommunicated and deprived of his title by Pope Gregory VII, Boleslaus died in exile in Hungary.
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