There are many sources proving the presence of Ostiglia Old Castle Towers. Nowadays only three of the circle of walls can be seen. One of them is the tower in which is now placed the major bell, that at that time was the bell tower of S. Maria in Castello Church, nearby. The belfry has four wonderful mullioned windows with two lights and at the centre are placed four columns with capital. Besides, the actual clock tower, linked to the bell tower by an impressive passage, had been equipped  with a drawbridge and was the entrance of Ostiglia Castle in the past.