In addition to voting by colleges or councils, the Imperial Diet also voted in religious coalitions, as provided for in the Peace of Westphalia. The Archbishop of Mainz presided over the Catholic body, or , while the Elector of Saxony presided over the Protestant body, or . The division into religious bodies was on the basis of the official religion of the state, and not of its rulers. Thus, even when the Electors of Saxony were Catholics during the eighteenth century, they continued to preside over the , since the state of Saxony was officially Protestant.