 The church was briefly the cathedral of the Diocese of Westminster created from part of the Diocese of London in 1540, by letters patent which also granted city status to Westminster, a status retained after the diocese was abolished in 1550.The Westminster Court of Burgesses was formed in 1585 to govern the Westminster area, previously under the Abbey's control.The City and Liberties of Westminster were further defined by Letters Patent in 1604, and the court of burgesses and liberty continued in existence until 1900, and the creation of the Metropolitan Borough of Westminster.