Two fortresses were built; in different times the current Koules, which dominates the edge of the harbor of Heraklion, and a smaller one just opposite of it, which was demolished in the early 20th century to improve the operation of the port. The small fortress built by the Venetians, for supplemental defense of Candia, was named “Rocca al Mare” (Sea Fortress). After the invention of gunpowder, the Venetians decided to create a larger building that could meet their needs. The construction was completed in 1540. The building had two floors, with 26 rooms for various uses, including prisons. The Turks, who occupied the island in 1669 renamed it ‘Koules’ and decided to continue its construction. It is now preserved in a very good condition and is used for cultural events.