Crete in ancient times was not threatened by external enemies. The first external enemies of the island were the Romans. Therefore, till then, the fortification of cities was focused on internal enemies. After the Roman Empire (67 BC-330 AD) things changed radically. Crete became a province of the Eastern Roman Empire, which later transformed to the Byzantine Empire. At the same time, several civilizations started developing around the Mediterranean Sea.
Thus, Crete, because of its natural and geopolitical position, acquired great importance and became an "apple of discord" for the civilizations of the Mediterranean. During the First Byzantine Period (330-824) things looked calm. For that reason, combined with the internal and external problems of the Empire, the island was on the fringes of the Byzantine interest. Thus, pirate raids increased and the seaside monasteries were fortified to protect themselves.
Under these circumstances, the first storm on the island was imminent. The Saracen pirates managed to easily occupy Crete in 824, that was almost defenseless. They settled for 140 years, till 961, during which they fortified the largest town, today’s Heraklion. After continuous failures to reoccupy Crete, Nikiforos Fokas managed to free the island from pirates in 961. Then, the Byzantines built new walls, which managed to keep invaders away for a few more centuries.
In 1206, Crete passed into the hands of the Genoese, who immediately gave particular importance to the fortification of the island. Within a few years the fortified three castles and 12 fortresses, but still the Venetians managed to occupy the island in 1209. The Venetian Era in Crete lasted for 4.5 centuries and was mainly dependant on the colossal fortification structures. The best Venetian engineers built the Great Castle of Candia (Heraklion). The Turks managed to take over Candia in 1669 after 22 years (!) of besieging and immediately started restoring the Venetian Forts and built a lot of small fortresses across the Cretan Territory, called Koules. The Turks took care of their forts till the end of their presence on the island.
Even today, visitors can get an idea of what the fortified cities of Crete were like, as the walls are still in excellent condition. The impressive castles in Chania, Rethymnon and Heraklion and the fortresses on the islands of Souda, Gramvousa, Spinalonga are but a few samples of Cretan fort architecture.
The imposing medieval fortress of Koules still stands at the beginning of the western breakwater of the modern port of Heraklion. Its real name is Rocca al Mare, named so by its Venetian founders. Koules, or the Great Koules like it is called, was not the sole ruler of the port.
The fortress of Apicorno has been one of the most important forts of the Gulf of Souda. The Castel Apicorno or Bicorna gave its name to the province of Apokoronas, called like this even today, although the fort is destroyed.
The fort Castel Belvedere or Kastelos was built on the isolated hill Kastellos, that was accessible only from its south side, near the villages of Ano and Kato Kastelliana. Here was the site of the ancient city Priansos, a powerful and great town that minted its own currency and had its seaport at Inatos (current Tsoutsouras).
The fortress Castel di Beto was located east of the village Meleses, close to Del Cornaro, and was only accessible from its west side. On the top of the hill, there are still ruins of the 0.65m wide wall and remains of a tower, a tank, a church, several other buildings and houses. Moreover, nearby there is a Venetian fountain dating in 1594.
The Fort Bonifacio or Apano Castelli is located west of the current Tsifout Kastelli village, 44km south of Heraklion, on a hill now called Apano Kasteli or Psilo Aloni. The fort is reported since 1212 and was built by the Genoese pirate Henry Pescatore.
Castel del Corner or fort of Paleochora is located on the hill Kastelos south of Katalagari village, at an area full of olive trees and vineyards. According to tradition, it was built by Nicephorus Phocas after the liberation of Crete by the Arabs in 961 AD.
On the west side of Chania harbor, the traveler can still visit Firkas fortress, still dominating a low hill and housing the modern Naval Museum of Crete. Firkas is a Turkish name and means division, as the fort housed the headquarters of the Turkish Division.
Next to the village of Krya, 25km away from the town of Sitia, there is a hill with the church of St. George and the ruins of a Venetian castle, called Monte Forte or Apano Castelli (Upper Forth).
Fortezza is a suburb of Heraklion, built on a high hill next to the hospital of Venizelion. This hill was ideal for establishing a fortress, as evidenced by its name.
The village Charakas took its name after a large rock (charakas in Cretan dialect) on which we still see the ruins of the small Venetian fort and the church of the Transfiguration, which was restored recently. The fort consists of three rooms in which the floor is carved into the rock and covered with plaster.
The fort Malvicino or Malvesin is located on a hill near the village Keramoutsi at a position that now is named Castel Malevizi. It occupied an excellent position in the inner land, which offered great views over almost the entire province of Malevizi (getting its name after the castle).
The fort of Intzedin is the only fort on Crete built by the Turks, located on the hill Kalami, 15km east of Chania and has a panoramic view to Souda Gulf. The fortress of Intzedin was built in 1872 by Reouf Pasha, on the same location where in 1646 the first Turks built a tower, chasing away the Venetians. It was the main defense construction of the port and was named "Intzedin" to honor the first born son of the Sultan Abdul Aziz Intzedin.
The fortress of Agios Nikolaos of Kyriakosellia is located in the homonym settlement of Kyriakosellia, belonging to the province of Apokoronas. It was a Byzantine fortress built by the feudal lord of the region to secure his privileges.
Kastelli in Kissamos, which in 1966 was renamed to Kissamos, is a small picturesque town built in the gulf of Kissamos or Myrtilos, between the peninsulas of Gramvousa and Spatha. The name derives from the Venetian fortress that was built there, remains of which still exist.
The fort Kales was built by the Venetians in the 13th century AD, to protect the town of Ierapetra from its enemies. In 1508 it was destroyed by an earthquake and the Turkish raids. The damage was not repaired, perhaps because it was very serious and there was no funding.
Castle Kazarma (Casa di Arma) is built on a hill near the port of Sitia, reminding of the old times that it protected the town. The fort is the only surviving part of the old town walls, which were destroyed by the Venetians.
The fort of Liopetro was located in Fatsi position, near the village Hamezi (Sitia province). It is believed to have been built on the site of an older fort, of which the tank survives. Liopetro is built on a steep hill with panoramic views to all sides. Atop of it, there is the scenic chapel of Prophet Elias and the remains of walls, tanks and other buildings.
The Fort of Kavalos is located at an elevated position east of the village Larani and apparently belonged to a lord of the area who wanted to control his lands.
Close to the scenic village of St. Thomas (Agios Thomas) in Heraklion there are the ruins of one of the largest fortification works in the Cretan inland. Atop of a high hill overlooking the valleys of the Prophet Elijah and Venerato, you will find the ruins of Melissa fortress build during the 2nd Byzantine Era (11th- 12th century).
In the province of Mylopotamos, one more mountainous provinces in Crete, there were two fortresses. The first was built in the seaside village of Panormos, while the second near th village Saint Mamas.