From the 5th century BC on, the city of Kavala was surrounded by a defensive wall. This was repeatedly modified over time. Extensive modifications and repairs were carried out after the Roman period by Emperor Julian (361-363), then by Justinian , and again in 926 by Basil Cladon, general of the Theme of Strymon.
A major modification took place in 1307 during the reign of Andronicus II Palaeologus when the long walls from the sea to the top of the hill were built. The fortifications incorporated the city's water supply, following the earlier model applied by Justinian to Anastasioupolis.
The Byzantine castle was completely destroyed in 1391 when the Turks captured the city.
The castle was rebuilt by the Ottomans in 1425 and what we see today is mostly the result of that reconstruction.
Structure, Fortification & Buildings
Following the lie of the land, the defensive wall girdled the hill, encompassing an area of 13 hectares. The enclosure was reinforced by round and square towers and bastions, mainly on the most vulnerable land side to the north. The perimeter is closed off by a transverse wall 449 metres in length, which climbs a steep slope to the most inaccessible cliffs on the north side to a height of 64 metres. The wall had four gates to facilitate movement into and out of the city. As part of the rebuilding projects carried out to reinforce the city’s defences, the citadel of Byzantine and Ottoman times was built on the hilltop site of its ancient counterpart.
The irregularly shaped citadel fortifications include the northern part of the city’s defensive walls, reinforced by two square towers on each of the northwest and northeast corners, a polygonal tower on the east side and a bastion on the southeast. The area inside the citadel is divided in two by a transverse wall running northwest - southeast, crowned at the central, highest point by a cylindrical tower.
The city’s defences also included a 1.5 km long wall, which written sources attribute to Andronicus II Palaeologus, between 1307 and1308. It was built on the occasion of an unsuccessful attempt by the Catalans to conquer Kavala, and was primarily used to control the road leading from Macedonia to Thrace via the city. This cross fortification began on the north side of the city walls and led to the opposite hills, interrupted only by the aqueduct. It ended in three square towers and one round one.