bolesław i the brave (polish "bolesław i chrobry") (967 june 17, 1025) was the duke of poland from 992 to april 18, 1025 and king of poland from april 18 to june 17, 1025.he was also a duke of bohemia known as boleslav iv from 1003 to 1004. he was the son of mieszko i, first known ruler of poland.