The Old Castle goes back to a water fortress built in the 10th century for the protection of the stud garden (which gave Stuttgart its name). After the counts of Wuerttemberg moved their residence (Rotenberg) to Stuttgart in the 14th century, the fortress was enlarged corresponding to the new function. In 1325, in the place of old building parts, the Dürnitz building, the "court hall" of the closest entourage, was built.
Duke Christoph von Wuerttemberg (1550 - 1568) was the first to place the character of the castle in the foreground. He had the old fortress redecorated in the inner court to a magnificent renaissance palace. The building masters were Aberlin Tretsch and Blasius Berwart. The Dürnitz building was given upper floors, three wings were added - the result was a facility with four wings which surrounded an almost quadrangular inner court decorated with arcades, the columns of which were created in the image of antique Corinthian models. From a stairway in the middle of the court, one could reach the upper floors and the Knight's Hall on a horse. In one wing the protestant castle church was included and dedicated in 1562. To the outside, the castle retained its medieval character in spite of many reconstructions.
The palace finally no longer lived up to the demands of a proper court in the 18th century. After Duke Carl Eugen had the New Castle built from 1746, the glorious days of the Old Castle were over and it was degraded to an accessory building. Officials of the Stuttgarter court moved in with their families. At the end of the 19th century, it was the seat of the royal collection of antiquities.
In December 1931, a fire destroyed the Dürnitz building and two towers. The repairs were not yet finished when a bomb attack again caused devastating damage in 1944. But as early as 1946, under the direction of Paul Schmitthenner reconstruction began and was completed in 1962 with the reconstruction of the renaissance inner court. Today the outside of the building corresponds vastly with that of the former residence castle of the reformation period.
Since 1948, the Württemberg State Museum has been located in the Old Castle. Its historic core goes back to the art chamber, founded by King Wilhelm I von Wuerttemberg, which was the result of the ducal passion for collecting since the 16th century. Everything was brought together which was rare, costly and unusual. The crown and scepter as well as the diamond jewelry of the queens bear witness to the Wuerttemberg kingdom. Today the museum places an emphasis on showing the history of the state from the stone age through the Celts, Romans, Alammani up to the middle ages, Baroque and modern times. Further valuable collections complete the exhibitions. The childrens museum "Junges Schloss" is also located in the Old Castle nowadays.
