The Altes Schloss or old castle, originally – since the 13th century – the heart of an extended hunting ground, surrounded by moats and equipped with numerous ancillary buildings, today forms an important visual motif in the gardens. After the lords of "Lachsenburg" had died out, the Habsburgs acquired the entire grounds in the 14th century. Under Albrecht III, this hunting castle was expanded and developed. In the second half of the 17th century, after a period of decay, Lodovico Burnacini (the famous theatre architect of Emperor Leopold I.) renovated the park in the baroque style. After an attack by the Turks in 1683, this building was reconstructed in 1693 and another floor was added. Until World War I, together with the Neues Schloss (the new castle), built in the 18th century, the Altes Schloss served as a spring residence for the Habsburgs. Between the WWI and WWII, it was home to the "HELLERAU-LAXENBURG" school for RHYTHM, MUSIC and PHYSICAL EDUCATION.
The sloping nature of the grounds had always made it difficult to lend them a regular design. The Renaissance garden constructed "in the Dutch manner" was, in the 16th century, somewhat remote, being located roughly in the area of todays theatre, and had no axial relationship to the Altes Schloss, which would then, in the baroque period, be integrated into the system of coordinates of avenues and lanes of an enlarged south-facing park. Located between this and the Uhlefeldhaus (originally to the south of the theatre, today no longer there) was a semi-circular large square with avenues of trees running through it, which was first included in the landscape design of the park during the first third of the 19th century.
Between the 1750s and 1770s, it was also considered whether this space should be made more attractive as a "park entrée" and even be flanked with buildings. The water basin with fountain dates from this period. The moats of the Altes Schloss were filled with earth in the second half of the 18th century and designed to as sections of lawn.