Koules Fortress of Heraklion, Crete, Greece

The "Fortress on the Sea" Venetian castle of the port (Rocca al Mare the name given by the Venetians) is perhaps the most characteristic sight of Heraklion.
Koules is the name of the sea fortress built by the Venetians in Heraklion. It is located at the entrance of the Venetian port, in order to protect the port of Heraklion and together with the Castle of Palaiokastro the bay of Ammoudara from the invasions and landings of other conquerors. It is also known as Castello del Molo (Castello del Molo), Rocca a Mare (Rocca a Mare), Castle of the Sea (Castello a Mare), Castle of Candia or former Ditch (Castel di Candia).
Koules is the name of the sea fortress built by the Venetians in Heraklion. It is located at the entrance of the Venetian port, in order to protect the port of Heraklion and together with the Castle of Palaiokastro the bay of Ammoudara from the invasions and landings of other conquerors. It is also known as Castello del Molo (Castello del Molo), Rocca a Mare (Rocca a Mare), Castle of the Sea (Castello a Mare), Castle of Candia or former Ditch (Castel di Candia).
General info about the Fort
The Fortress was built by the Venetians, during the first years of their rule in Khandaka, to better protect the city's port, which had prominent strategic and commercial importance. The original building, which was low and without a slope, was destroyed by the earthquake of 1303 and was repaired
At the beginning of the 16th century, as part of the general redesign of the city's fortifications, the old fortress was demolished and in its place was built the fortress that has survived to this day in the period from 1523 (chronology mentioned in an inscription above the northern gate) until 1540..
Representation of Cantia, capital of Crete, by Francesco Valegio (1595), where we see, metaphorically, the Venetian fortress, on the right, represented by a tower (perhaps the author did not realize that he never visited Crete and relied on earlier writings in the construction of the Koules fortress, when there was only one tower).

Its massive buildings were carried over from Frascia and Dia. The fortress has two floors and in its final form covered an area of approximately 3,600 sq.m.
The ground floor is divided by thick walls into 26 apartments that served as food and munitions stores, but also as prison cells, in which many Cretan rebels were tortured. Accommodations for the castellan and the officers of the guard had been arranged on the floor. There was a bakery, a mill and a small church. Portholes were opened on the three sides facing the sea for the cannons that protected the port.
Here, the earliest representation of a canon in Europe, De Nobilitatibus Sapientii Et Prudentiis Regum Walter de Milemete, 1326.

In 1630 there were 18 guns on the ground floor and 25 on the first floor. A ramp used to transport the machine guns led up to the roof. On the NE, W and S sides on the outside were built-in marble reliefs of the winged lion of Venice which today are preserved mutilated. The ramparts of the fortress have been restored.
Older fortifications
The old port of Heraklion was created in a natural bay whose northern side was surrounded by a series of rocks and reefs, on the northern coast of Crete.
On the edge of these rocks the Venetians built a tower in the first years of their rule on the island. It has not been confirmed whether a Byzantine or Arab tower previously existed in that location. This tower was probably circular and was seriously damaged by the earthquake of 1303, as mentioned by Duke Quito da Canal in his report to Venice.
A new tower was built in its place, which was referred to as Torre del Castello. It is not known what form it took. Cristoforo Buondelmonti in 1429 designed a tall square tower at the entrance of the port, while Erardo Revic in 1486 designed a tall circular tower with ramparts built on a terraced terrace, with a smaller circular tower on the other side of the port. This tower suffered significant damage from earthquakes in 1508 and 1517. 
In the summer of 1523 the engineer Antonio Saracini, Giovanni da Como, the army chief Tommaso Mocenigo and Duke Marco Minio judged that the tower was inadequate to withstand the attacks with firearms and ordered its demolition and the construction of a new, stronger fortress .

Construction and maintenance
Construction of the new fort began immediately. It is not known who designed the fort, but it is possible that they were designed by Antonio Saracini or Giovanni da Como. Tommaso Mocenigo proposed a fortress on the model of the fortress of Agios Nikolaos in Rhodes and asked whether the fortress would be in the form of a tower or a barracks, i.e. a large fortress with bastions. The response he received is not known.
Construction began with the creation of the fort's underwater base. To build it, the Venetians filled old ships and boats with stones and sank them. The stones came from the island of Dia and Fraskia. By November 1530 about 16 meters (9 passi) of foundation. Alessandro Cantarini three weeks later reported that the construction work on the outer walls had progressed and after a while work on the interior would also begin.
Thc construction was interrupted in the winter due to adverse weather conditions. In 1533, a large white relief of the lion of Saint Mark was placed over the entrance of the fortress. In 1539 it was built over the staircase to the first floor, indicating that it was then completed. The work was completed in 1540.
It then underwent repeated repairs due to wear and tear from the waves. The Venetians constantly strengthened the north-west side, which was battered by the waves, with new boulders and protective embankments. In 1552, the breakwater that was located on the northern side of the fortress and protected it from the waves partially collapsed. Another problem faced by the authorities was the sedimentation in the port. To deal with the problems, Gianmatteo Bembo proposed rebuilding the fortress, extending it to the northeast, in an area of shallow water. In September 1556 the pier was almost rebuilt. Its base consisted of two rows of blocks weighing eight to ten tons joined by metal links and lead. But two years later, an already significant part of it had been destroyed again.
In 1566 Giulio Savornian proposed that the outer wall of the fort should have a sloping surface to make it more resistant to damage from the sea, which in bad weather could move the large blocks of the breakwater that protected the fort for a long distance. In 1570, during construction work on the roof of the fortress, a large hole was created in the pier, which could not be repaired. By the end of the 16th century many proposals were made to protect the fortress from bad weather, while the pier was almost completely destroyed and cracks had appeared in the walls and the foundations had been undermined to such an extent that sea water reached the freshwater tank water of the north side. A new breakwater was created, but it was washed away by the waves in a short time. Due to the damage to the castle's foundation, Venice sent a significant financial sum for its repair.
The winged lion of Venice on the north side of the Kule.

Despite the high maintenance costs, the fortress played a minor role during the siege of Khandaka by the Ottomans. The Ottomans at the end of the siege neutralized the firepower of the fortress with cannons they set up in the area of Trypitis and siege engines they set up in Sampionara, and thus gained control of the port.

Koules in 1919, by Frédéric Boisson.

Ottoman and later times
Immediately after the conquest of the city, the Turks repaired the damage caused by the cannons and built the mosque of the arch-admiral Kaplan Mustafa Pasha in the vicinity of the fortress. The fortress was described by Evliya Celebi during his travels, and mentions that it was called Su Kalasi or Su Kulesi (fortress or tower of the sea). Constant repairs continued even after the occupation of Khandaka by the Ottomans in 1669. In 1719 part of the northwest side of Kule collapsed but was repaired again. The cost of the repair, together with other work at the port, amounted to 5,000 gros. At the same time it functioned as a prison. When Bonval and Dumas visited it in 1783 they found it in a very poor condition. They described it as having two rows of machine guns. During Ottoman times, another, smaller tower was built on the eastern jetty to strengthen the defense. In a census of 1703 it is mentioned as Neos Pyrgos, while it remained known as Mikros Koules. It survived until 1936, when it was demolished.

At the beginning of the 20th century, buildings were built on the roof of Koule for the service of the lighthouse keeper and sea scouts. About 1920 electricity poles and a crane were added. The extension of the jetty improved the stability of the fortress, which had been dug back from the sea. During the Second World War and the bombing of Heraklion, the crane was destroyed.

The first restoration works of the fortress began in 1959 and were carried out under the supervision of Stylianos Alexios. They included the replacement of crumbling Ottoman ramparts with new ones and the removal of newer additions. More intensive work took place in the period 1972-1975, which aimed to transform the fortress into a monument to be visited, with work on the roof, such as the construction of cannon ports, a perimeter elevated corridor and parapets on the skylights and configuration of the interior spaces. In 2000, support work was carried out on the south side because it had been caved in by the sea.
The fortress is built on the western promontory of the port of Heraklion, at the northern end of the pier of the old port. It is two-storey and covered approximately 3,600 sq.m. Its plan is square, with a large semicircular projection on the eastern side.
The entrance to the fort is on the west side of the fort, at the edge of the jetty. A smaller entrance is on the north-east side, and led to a semi-circular jetty, and another on the south side, towards the harbour. The fortress is built with massive structures brought over from Fraskia and Dia. The outer walls of the fort are very thick. The thickness on the east, west and north-east sides is 8.7 meters, while on the north side it is about 7 meters. The inner walls are thinner, with a thickness of 1.4 to 3 meters, depending on the location.
From the western entrance begins a slightly downhill corridor 10.5 meters long and 3 meters wide, which had three doors for its defense. The corridor then becomes wider, with a width of 7 meters, which then branches into two corridors.
One corridor heads north, towards the narrow side of the building, where there was an auxiliary door, and the other towards the east, where the semi-circular projection is located. The floor of the ground floor has a slight slope, with the west side being lower than the east. The ground floor is 1.36 to 1.74 meters above sea level.

On the ground floor it is divided into 26 apartments that were mainly used as food and munitions stores, but also as prison cells. Also there was a large water tank. The ground floor ceiling is vaulted and has large openings for lighting and ventilation. On the floor there were rooms for the officers together with a bakery, a mill and a small church. On the three sides facing the sea, hatches were opened for the cannons that protected the port. In 1630 there were 18 large cannons on the ground floor and 25 of various calibers on the first floor. On the NE, W and S sides on the outside were built-in marble reliefs of the winged lion of Venice which today are preserved mutilated
The ground floor communicated with the first floor with a staircase and an inclined level. From the inclined level the Venetians could slide cannons and munitions upstairs. The floor consists of a large courtyard and perimeter curtain. The floor of the storey is 10.4 meters above sea level, while its south-west edge is at a lower level, at a height of 8.7 meters above sea level. Above the curtain was Kule's shooting plane. The curtain has two levels, with the west and south-west sections being higher than the north. The ramparts of Kule were built by the Ottomans. On the eastern side there is an opening from where supplies could be loaded and unloaded from the harbor directly onto the roof.

During the period of Egyptian rule in Crete (1830-1840), a lighthouse was built on the northeast corner of Koule. In 1930, concrete pillars were added to the lighthouse. The lighthouse was destroyed in World War II, but was rebuilt and continued to operate until 1960, when it was renovated and the concrete pillars removed.
Today Koules can be visited, while it is also used for cultural events. Restoration works are carried out periodically and the fort remains open to the public
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