The Emperor himself was chosen, as we know, by three ecclesiastical electors, the Archbishops of Koeln, Trier, and Mainz, and by four princes, the Pfalzgraf, called in English the Elector Palatine, the Markgraves of Saxony and Brandenburg, and the King of Bohemia.

The princes and other potentates, owing immediate allegiance to the empire alone, were practically independent sovereigns.

The Reichstag, instituted in the fifteenth century, attendance at which was strictly limited to these immediate vassals of the empire, had proved of little effect.

This was shown when in the middle of the sixteenth century Protestantism had established itself in the favour of the mass of the German peoples.

It was vetoed by the Reichstag, with its powerful contingent of ecclesiastical members.