An old German town in Hesse-Darmstadt, in a fertile plain on the left bank of the Rhine, 40 m. SE. of Mainz, with a massive Romanesque cathedral having two domes and four towers; it was here the Diet of the empire was held under Charles V., and before which Martin Luther appeared on 17th April 1521, standing alone in his defence on the rock of Scripture, and deferentially declining to recant: "Here stand I; I can do no other; so help me God."