The seven Electors would be the Archbishop of Cologne, the Archbishop of Mainz, the Archbishop of Trier, the Margrave of Brandenburg, the Duke of Saxony, the Count Palatine of the Rhine and the King of Bohemia. They met in Frankfurt to vote on who would be ‘King of the Romans’, the idea being that it was only the Pope could crown an Emperor – a distinction that would be dropped by the Habsburgs, who generally had their heir voted as King with the title of Emperor automatically being acceded to on the current holder’s death.
