In the Middle Ages, a castle was built, surrounded by a moat; later it was converted to a chateau. Its facade as seen today is in the "Josephinian Style", a late and very rare Baroque style that only was used during the reign of Emperor Joseph II in the late 18th century. The chateau (Schloss Rohrau) has been owned by the Counts of Harrach and their descendants since 1524, and it contains the largest private collection of Dutch oil paintings in Austria.