In 1020, King Canute elevated Roskilde to a bishopric, giving it high national status. Absalon, the Danish bishop, had a brick church built on the site of Harald's church in 1170. Today's cathedral was completed in 1275 after five of Absalon's successors had contributed to its construction. As a result of Absalon's influence, many other churches were built in the vicinity, making Roskilde the most important town in Zealand. Coins were minted there from the 11th to the 14th century. In 1150, Sweyn Grathe built a moat around the city. In 1151/2, a religious confraternity was founded for the defence of the town against Wendish pirates. Under the command of Wetheman, it also took part in the Wendish Crusade. The Roskilde bishops owned large areas of land in the region including, from 1186, Havn on the Øresund which later became Copenhagen. By the time of the Danish Reformation in 1536, there were 12 churches and five monasteries in the city.