Drena - Castles, palaces and mansions Castel Drena The castle was built in the twelfth century on a hill, in the homonymous location from which it also took its name. The purpose for which it was built was to control the connection route between Trento and Lake Garda. This was one of the reasons why it was always contested over the centuries. During the last restoration works, traces were discovered dating back to the Bronze Age period.