Old Castle, Renaissance castle and museum in Stuttgart-Mitte, Germany

The Old Castle is a Renaissance residence with stone walls, defensive towers, and a spacious inner courtyard in Stuttgart's city center. The building now houses the Württemberg Museum with extensive collections of regional art and cultural items.

Archaeology under the south wing found settlement traces back to the 8th century and a Hohenstaufen castle of the late 12th or early 13th century, not the 10th. Around 1300 a new castle with walls about 3.6 metres thick was built, rotated some 45 degrees, and became the seat of the Counts of Württemberg. From 1553 Dukes Christoph and Ludwig had Aberlin Tretsch and Blasius Berwart convert it into a Renaissance palace, demolishing about 60 percent of the old fabric for the arcaded courtyard.

The arcaded courtyard shows early Italian Renaissance motifs and was conceived as a tournament square, with representative arcades originally meant to run around the entire courtyard. In the inner courtyard stands a monument to Eberhard I. The castle church in the southwest wing was consecrated in 1562 and still serves worship; King Charles I of Württemberg and his wife Olga are buried beneath it.

The museum entrance and the Stauffenberg memorial are on the Karlsplatz side of the complex, while the castle church occupies the southwest wing. The arcaded courtyard can be crossed on foot between Schillerplatz and Karlsplatz. The church still holds services, so access there depends on worship times.

The arcaded courtyard was conceived as a tournament square, and its Italian Renaissance arcades were originally meant to run around the whole courtyard. The building also holds a memorial to Claus Graf Stauffenberg, who was executed on 20 July 1944; its entrance is on the Karlsplatz side.