Kassiopi Castle was one of three Byzantine-period castles that defended the island before the Venetian era (1386–1797). The castles formed a defensive triangle, with Gardiki guarding the island's south, Kassiopi the northeast and Angelokastro the northwest.
The exact origins of the castle are not clear, with various theories being advanced, but they appear to be Byzantine. During excavations in the two towers adjacent to the main gate as well as in a third tower to the north side of the main gate, bronze coins from the reigns of Byzantine emperors Maurice (582–602 AD) and Basil II (976–1025) were discovered.
In addition ceramic ostraca dating from the early Byzantine period, the 4th–7th centuries AD, were also unearthed. This leads to the conclusion that a Byzantine castle may have been built in the area by the 6th century AD, a date which is several centuries earlier than the currently estimated date of the present castle's construction.
In 1081 Count Bohemund of Taranto conquered the castle at the start of the first Norman invasion of Greece. In 1084 the fortress fell into the hands of Alexios I Komnenos after he defeated the Norman fleet following three naval battles in the Corfu Channel. In 1267 the Angevins took over the castle and in 1386 the castle fell to the Venetians after some initial resistance.
The Venetians ordered the destruction of the castle because its defenders resisted their takeover of Corfu in 1386 and did not willingly surrender. The Venetians subsequently dismantled it, fearing it could be captured by their enemies, or by the locals, and used against them. Even in later times they did not repair or maintain it, in contrast to their efforts at strengthening Angelokastro and the Old Fortress of Corfu. The consequence of the Venetian action was that during the Turkish sieges of Corfu in 1537 and 1716 the local people who could not escape were slaughtered or enslaved.
After the 1669 Venetian surrender of Candia in Crete to the Ottomans, Corfu became the last Venetian possession and bastion in the Levante. Consequently, the Venetians redoubled their efforts at strengthening the defences of the island. In 1671 a Venetian official by the name of Dona was sent to evaluate the defences of Corfu and submit a plan to the Venetian Senate.
Donna went in situ to Kassiopi to evaluate the castle and its prospects of defending Corfu from the Ottomans who were planning an invasion of the island from Epirus. Dona went along with Venetian special commander of the Adriatic, and future Doge of Venice, Mocenigo. Based on further advice by general St. Andrea and military engineer Verneda, Dona's report to the Venetian Senate supported the strengthening of the Kassiopi Fortress. Despite Dona's advice the Venetians abandoned all plans of defending Kassiopi.
Following the second great siege of Corfu in 1716, the Venetians finally decided to rebuild the castle, although the local population had already moved to other places including villages on the highlands of Mount Pantokrator.
The perimeter of the castle has a length of c. 1 km and is of a quadrilateral shape with 19 strong towers of alternating circular and rectangular cross sections guarding the walls and runs in the southwest to northeast direction. The interior of the castle has an area of 35,177 m2 and is empty of any structures although filled with olive trees. The central tower of the castle has disappeared but the main gate exists and is supported by two strong towers on either side.
Each of the gate towers has two floors and the gate features protective wall extensions which restrict access from the sides, a feature which is designed to prevent surprise ambush from an enemy hiding at the side of the gate. The ambush avoidance feature is further augmented by the terrain which slopes upward at the gate. The thickness of the wall at the gate is 1.9 m. There are ruins of a forewall in front of the gate which could have functioned as an installation of a large iron structure which would have secured the gate.
There are indications that both strong towers at each side of the gate had installations that facilitated the movement of the iron gate closure. The defence of the castle was mainly achieved through warfare from the battlements, although no battlement structures survive. The shape of the battlements is uncertain and although in artistic representations they look like the letter 'M', it is still not known if that representation is simply the artist's imagination.
Since the walls of the castle are vertical, and not inclined so that cannon projectiles could bounce off them, the design was meant to repulse conventional siege machinery developed prior to the advent of artillery. Such conventional equipment would have included ladders, siege towers, and battering rams. The overall design of the castle is modest and characteristic of its provincial origin. The rectangular towers are older than the cylindrical ones and there are indications that the technology of the cylindrical towers may have been belatedly introduced to the fortress, given its rural and provincial location.
Since the castle was abandoned for a long time, its structure is in a state of ruin. The eastern side of the fort has disappeared and only a few traces of it remain. There are indications that castle stones have been used as building material for houses in the area. Access to the fortress is mainly from the southeast through a narrow walkway which includes passage from homes and backyards, since the castle is at the centre of the densely built area of the small village of Kassiopi.References:
Varberg Fortress was built in 1287-1300 by count Jacob Nielsen as protection against his Danish king, who had declared him an outlaw after the murder of King Eric V of Denmark. Jacob had close connections with king Eric II of Norway and as a result got substantial Norwegian assistance with the construction. The fortress, as well as half the county, became Norwegian in 1305.
King Eric's grand daughter, Ingeborg Håkansdotter, inherited the area from her father, King Haakon V of Norway. She and her husband, Eric, Duke of Södermanland, established a semi-independent state out of their Norwegian, Swedish and Danish counties until the death of Erik. They spent considerable time at the fortress. Their son, King Magnus IV of Sweden (Magnus VII of Norway), spent much time at the fortress as well.
The fortress was augmented during the late 16th and early 17th century on order by King Christian IV of Denmark. However, after the Treaty of Brömsebro in 1645 the fortress became Swedish. It was used as a military installation until 1830 and as a prison from the end of the 17th Century until 1931.
It is currently used as a museum and bed and breakfast as well as private accommodation. The moat of the fortress is said to be inhabited by a small lake monster. In August 2006, a couple of witnesses claimed to have seen the monster emerge from the dark water and devour a duck. The creature is described as brown, hairless and with a 40 cm long tail.