English: The entrance to the Gramvousa fortress. Gramvousa is an islet very close to the NW coast of Crete, in a strategic position for the control of the channel between Crete and Antikithira (Cerigotto).

The Venetians fortified Gramvousa to have an early alert of possible corsair raids and to provide a temporary haven to convoys in case of attack or storm. The island's eminent castle was built in 1579 at the highest point of the island, on top of a steep rock at a height of 137m. It is surrounded by a wall of 272m where the abrupt rock does not offer any natural fortification. It has a roughly triangular shape and each side is 1km in length.

Gramvousa was selected in 1669 by Francesco Morosini as one of the three fortresses (the other two were Souda and Spinalonga) to be retained by Venice after the loss of Crete to support the merchant navy on the route from the Ionian Sea to the Eastern Mediterranean. The fortifications were strengthened, but this did not help in 1715 when the Turks launched their attack against Venice. It seems that both Venetians and Turks had a Levantine approach to warfare and treachery was part of it: the commander and the garrison of Gramovuusa were bribed and the fortress fell into the Sultan's hands.

During the 19th century Greek uprising against the Turks, Gramvousa played an important and decisive role. After many attempts, the castle was finally conquered by Cretan rebels in 1825 when a group of Cretans, disguised as Turks, entered the castle. It became shelter for more than 3,000 Cretans and became a base of operations for revolutionary groups.

As conditions for survival were harsh, the residents of Gramvousa turned to piracy, indiscriminately looting boats passing between Gramvousa and the island of Antikythira, a fact that turned European opinion against them, and gained the island its pirate reputation. In 1828, with the agreement of the Greek government, fleets from England and France routed the pirates and occupied the castle. After signing the Protocol of London, Crete remained under Turkish occupation until 1831 and the castle of Gramvousa was handed over to the Turks once again by the Russian guard.