Erfurt is a city in the central German state of Thuringia. Martin Luther, father of the Protestant Reformation, was ordained in the Cathedral of St. Mary, whose origins date to the 8th century. Next to the cathedral is the Gothic Church of St. Severus. The Augustinerkloster is a monastery where Martin Luther lived as a monk. The Krämerbrücke bridge has medieval houses and shops, and stretches over the Gera River.