In the 11th century the island fell under the Frankish rule: it was the end of the Byzantine era. From then, the Normans, the Orsinis, the Andeans and the Toccans successively conquered Kefalonia.

The first Turkish attack was effectuated by the famous Ahmed Pasha, in 1480. Pasha and his troops ruled on the island for a short period of time but, when they left, they devastated the island. Following the faith of the rest of the Ionian Islands, Kefalonia came under the domination of the Venetians and the Spanish. The political and military center of the island during this period was Saint Georgios Fortress but because it was destroyed by an earthquake in 1757, the capital moved to Argostoli, where it still is today.

During the Venetian domination the atmosphere was quite conflictive because the island’s society was divided into three classes and the noble class, which was the wealthiest and more powerful, had all the privileges and used them against the other social classes.

The Venetian rule ended in 1797 with the arrival of the French who were warmly welcomed by the island’s inhabitants because Napoleon promised them to liberate them (and the rest of the Ionian Islands) from the oligarchic system created by the Venetians. The French publicly burnt the Golden Book where the names and privileges of the nobles were written.

The French were defeated by the allied fleet of the Russians, the Turks and the English. The Ionian State was founded in Constantinople in 1800 and was under the Sultan's supervision. The nobles of Kefalonia island took their privileges back.

After popular demand democratic elections were organized in 1802 and a new Constitution was established in 1803.

Kefalonia island fell again under French domination in 1807 but the new Constitution was maintained. After the Treaty of Paris, in 1809, the Ionian Islands came under the rule of the English and the “United States of the Ionian Islands” was established. During the English period various important constructions of public interest were constructed.

Despite the fact that Kefalonia, like the other Ionian Islands, remained under the English rule and escape the Turkish yoke, its inhabitants financially helped the Greek Revolution for independence against the Ottomans who were ruling on the major part of Greece.

Kefalonia was finally united to the rest of independent Greece in 1864 with the rest of the Ionian Islands.

During World War II, in 1941, the island was occupied by the Italian troops which were allied with the Germans.

In 1943, Italy capitulated and its troops refused to leave from Kefalonia. As a punishment, the German forces killed more than 5000 Italian soldiers. This fact was described in the famous book (that became a movie) "Captain Corelli’s Mandolin", written by Louis de Bernieres.

In August 1953, the major part of Kefalonia island was destroyed by a huge earthquake.