Vaduz Castle (German: Schloss Vaduz) is the palace and official residence of the Prince of Liechtenstein. The castle gave its name to the town of Vaduz, the capital of Liechtenstein, which it overlooks from an adjacent hilltop. The former owners, who were presumably also the builders, were the counts of Werdenberg-Sargans. The bergfried (built in the 12th century) and parts of the eastern side are the oldest. The tower stands on a piece of ground that is 12 by 13 metres (39 by 43 feet) in area. At the ground floor, the tower walls have a thickness of up to 4 metres (13 feet). The original entrance lay at the courtyard side at a height of 11 metres (36 feet). The chapel of St. Anna was presumably built in the Middle Ages as well. The main altar is late-gothic. In the Swabian War of 1499, the castle was burned by the Swiss Confederacy. The western side was expanded by Count Kaspar von Hohenems (16131640). The Princely Family of Liechtenstein acquired Vaduz Castle in 1712 when it purchased the countship of Vaduz. At this time, Charles VI, Holy Roman Emperor, combined the countship with the Lordship of Schellenberg, purchased by the Liechtensteins in 1699, to form the present Principality of Liechtenstein.