In the Venetian harbour of Heraklion stands the fortress of Koules.
The Venetian harbour also contains the Venetian Arsenals or shipyards, where ships were repaired.
Opposite Koules, at the yacht moorage, is white building of the Heraklion Port Authority. Here stood Little Koules, which once guarded the entrance to Heraklion harbour along with the larger fortress.
The natural bay of Heraklion, which grew into the most important harbour of the Eastern Mediterranean over the centuries, was neither particularly large nor particularly deep, and definitely not leeward. The date of the first harbour installations is unknown, although eminent scholars have identified ancient cuttings in the rock.
The first serious attempt to create an organised harbour in the bay of Chandax came in the Arab period (9th-10th c.). Its vital position on the sea routes of the Eastern Mediterranean lent itself to the pirate raids of the Arab corsairs on the one hand, while the existence of a harbour served the exploitation of Cretan sources of wealth for trading with Islamic states on the other.
Following the restoration of Crete to the Byzantine Empire in 961 AD, Chandax gradually developed into a thriving city, and its harbour was consequently fortified and improved.
When the island fell into the hands of the Venetians (1204), Candia (as the Venetians called both the city of Heraklion and the whole island) became "the other Venice of the East". Its harbour was the only one in Greece to engage in the export trade on such a large scale. Especially during the last two centuries of Venetian rule, it was the greatest harbour in the Eastern Mediterranean. Its main exports were wine, olive oil, raisins, cheese, honey, beeswax, silk, cotton and salt, which was a Venetian monopoly.
Right from the start, the harbour of Heraklion silted up and had to be dredged constantly by the Venetians, using various methods of the time. In the 17th century the harbour acquired its finished form, able to moor 50 galleys (Francesco Basilicata, 1625).
Very few modifications were carried out to the harbour during the Turkish period (17th-19th century).
Unfortunately, the most destructive interventions in the harbour area were perpetrated in the 20th century, in order to turn Heraklion into a modern European city. In an age in which the idea of a "monument" was of no particular value, the introduction of the car into everyday city life led to the opening of the coast road, demolishing much of the Venetian harbour installations, Little Koules and the Byzantine Harbour Gate.