Clergy in the Roman Catholic Church are either deacons, priests, or bishops belonging to the diaconate, the presbyterate, or the episcopate, respectively. Among bishops, some are metropolitans, archbishops, or patriarchs. The Pope is the Bishop of Rome, the supreme and universal hierarch of the Church, and his authorization is now required for the ordination of all Catholic bishops. With rare exceptions, cardinals are bishops, although it was not always so; formerly, some cardinals were people who had received clerical tonsure, but not Holy Orders.