The manor, first mentioned in 1523, was for a longer period of time associated with the noble family of von Ungern-Sternberg. The Neo-Baroque castle, constructed on the manor grounds in 1890 (a copy of the Merseburg castle in Germany), was never finished. After World War II the manor fell into the hands of Soviet troops, in 1968 the chief of the airport decided to use the ruins of the manor to fill in the holes in the runway. About one third of the manor was torn down, fortunately the rest was preserved until today.
Sirmione castle was built near the end of the 12th century as part of a defensive network surrounding Verona. The castle was maintained and extended first as part of the Veronese protection against their rivals in Milan and later under the control of the Venetian inland empire. The massive fortress is totally surrounded by water and has an inner porch which houses a Roman and Medieval lapidary. From the drawbridge, a staircase leads to the walkways above the walls, providing a marvellous view of the harbour that once sheltered the Scaliger fleet. The doors were fitted with a variety of locking systems, including a drawbridge for horses, carriages and pedestrians, a metal grate and, more recently, double hinged doors. Venice conquered Sirmione in 1405, immediately adopting provisions to render the fortress even more secure, fortifying its outer walls and widening the harbour.
Thanks to its strategical geographical location as a border outpost, Sirmione became a crucial defence and control garrison for the ruling nobles, retaining this function until the 16th century, when its role was taken up by Peschiera del Garda.