The fourteenth-century Reichssaal in the town hall was the site of the Imperial Diet between 1663 and 1806. But Regensburg was devastated by French troops in 1809, and was ceded back to Bavaria in 1810. Regensburg's impressive medieval architecture survived the French assault, however, and much of it still stands, including the twelfth-century Steinerne Brücke (stone bridge) across the Danube and the Cathedral of Saint Peter (1275-1524). St. Emmeram's, a ninth-century Romanesque church, was significantly remodeled in the eighteenth century. St. Emmeram's Abbey in 1812 became the palace of the princes of Thurn and Taxis.