 From 968 until the Protestant Reformation, Merseburg was the seat of the Bishop of Merseburg, and in addition to being for a time the residence of the margraves of Meissen, it was a favorite residence of the German kings during the 10th, 11th and 12th centuries.Fifteen diets were held here during the Middle Ages, during which time its fairs enjoyed the importance which was afterwards transferred to those of Leipzig.Merseburg was the site of a failed assassination attempt on Polish ruler Bolesław I Chrobry in 1002.