Τhe castle of Agia Mavra was built around 1300 by the then Frankish ruler of the island Ioannis Orsinis and is located at the entrance of the island of Lefkada, near the bridge. Its name is probably due to the construction of a church inside, which was dedicated to Agia Mavra. Initially, it was built as a place for the military forces to gather in case of invasion or hostilities on the island but it was later evolved into an administrative center, as well as a place of permanent residence for dynastic families and the population in general. Interventions and extensions of the walls were carried out by other new rulers of the castle. The strong presence of the Jewish element inside the fortification is related to the persecution of the Spanish Jews by the King of Spain, Ferdinand, in 1492, while during the Turkish occupation, only Muslims lived in the castle. The castle was accessible through bridges -originally wooden bridges and during the English occupation stone ones- located over the water moats which were used for defense. Inside the castle, there was the center in the shape of a heptagon and around it three external walls. Ruins of buildings, most of which dating back to the Venetian rule, are preserved within the walls. They were altered significantly during the British occupation to serve as barracks or warehouses. In 1888, near the entrance of the eastern moat, a small single-aisled church of Agia Mavra was built as a continuation of the older church that operated in the castle since the years of the administration of the Tocco family.