Imperial Circle
The Thirty Years' War had prevented any Imperial Diet (German "Reichstag") from being summoned for thirty years: the last one before the war had been that of 1613. In 1623, the Emperor had summoned and dominated a Diet of the Princes at Regensburg. The rest of the states' corporate representation had been done on occasional days at the Imperial Circle and at the Electors' Diets of 1619, 1627, and 1630.