Ini­tial­ly, the Vene­tians called their fortress “Roc­ca al mare”, which is trans­lat­ed from Ital­ian as “Rock by the sea”. The fortress received the name “Kules” dur­ing the Turk­ish rule, the Turks called it “Su Kule­si”, trans­lat­ed from Turk­ish as “Water Tow­er”. In addi­tion to the fact that the Koules fort was a source of water, it was also used by the Turks as a prison, for impris­on­ing Cre­tan rebels here.

The Koules fortress con­sists of two floors. On the first floor there are 26 rooms, which con­tained food ware­hous­es and ammu­ni­tion depots, as well as prison cells.

Over the years of its exis­tence, the Koules fortress was repeat­ed­ly attacked and besieged for a long time, and in the 17th cen­tu­ry it wit­nessed dra­mat­ic events when, after an attack by the Turks, the Vene­tians lost one of the most pow­er­ful for­ti­fi­ca­tions in Crete and through­out the east­ern Mediter­ranean.