The fortress, built in about 1278 by Mastino I della Scala, Lord of Verona, probably on the remains of a Roman fortification. Thanks to its location, territorial becomes focal point of Scaliger and defense system of control of the Exchequer of Garda and its dock, still in perfect state of conservation, is a rare case of fortification intended to use port. The walls and the three massive towers are characterized by battlements, dovetail construction scaligere feature; behind these three towers emerges the imposing Tower, 47 meters high, under which cells were intended for prisoners. About a century later were added two courtyards and a private fortress connected via barbacane at the main one, to boost the defences of the fortress. In 1405 Venice annette Sirmione to his Republic and starts a work of strengthening and broadening of the now obsolete darsena degli scaligeri. The dock is also defended by towers but, unlike those inside the Castle, there are feature dovetail battlements. On one side of the dock continues an outer moat which leads directly to the Lake. The present appearance was defined during the restoration works carried out between 1917 and 1935. The visit of the mighty castle, completely surrounded by water, provides access to the courtyards through an arcade inside where you set up a Roman and medieval lapidary and past the drawbridge leading to the second fence, the ability to climb the tower and walls walkways from which you can admire the charming, old dock shelter scaligera fleet, and a beautiful landscape.