The "old town" (), on the south bank of the Neckar, is long and narrow. It is dominated by the ruins of Heidelberg Castle, 80 metres above the Neckar on the steep wooded slopes of the Königstuhl (King's chair or throne) hill. The Main Street (Hauptstrasse), a mile-long pedestrian street, running the length of the old town. The old stone bridge was erected 1786–1788. A medieval bridge gate is on the side of the old town, and was originally part of the town wall. Baroque tower helmets were added as part of the erection of the stone bridge in 1788. The Church of the Holy Spirit (Heiliggeistkirche), a late Gothic church in the marketplace of the old town. The Karls‘ gate (Karlstor) is a triumphal arch in honour of the Prince Elector Karl Theodor, located at Heidelberg's east side. It was built 1775–1781 and designed by Nicolas de Pigage. The house Zum Ritter Sankt Georg (Knight St. George) is one of the few buildings to survive the War of Succession. Standing across from the Church of the Holy Spirit, it was built in the style of the late Renaissance. It is named after the sculpture at the top. The Marstall (Stables), a 16th-century building on the Neckar that has served several purposes through its history. It is now a cafeteria for the university. Heidelberg Castle The castle is a mix of styles from Gothic to Renaissance. Prince Elector Ruprecht III (1398–1410) erected the first building in the inner courtyard as a royal residence. The building was divided into a ground floor made of stone and framework upper levels. Another royal building is located opposite the Ruprecht Building: the Fountain Hall. Prince Elector Philipp (1476–1508) is said to have arranged the transfer of the hall's columns from a decayed palace of Charlemagne from Ingelheim to Heidelberg. In the 16th and 17th centuries, the Prince Electors added two palace buildings and turned the fortress into a castle. The two dominant buildings at the eastern and northern side of the courtyard were erected during the rule of Ottheinrich (1556–1559) and Friedrich IV (1583–1610). Under Friedrich V (1613–1619), the main building of the west side was erected, the so-called "English Building". The castle and its garden were destroyed several times during the Thirty Years' War and the Palatine War of Succession. As Prince Elector Karl Theodor tried to restore the castle, lightning struck in