The name of the island (Kefalonia) derives from King Kefalus, who had married the daughter of the King and hero, Theseus. According to the legend, he came to Kefalonia because he had killed his wife. Kephalus' descendant, according to the historical researchers, is Odysseus, resourceful and ingenious hero of Homer.
Duding the Prehistoric Era, the level of the water of the island was 100 m. lower and it communicated by land with the rest of the islands of the Ionian Sea, as well as with the other coasts across sea. The researchers were drawn to the above conclusion, after discovering fossiled bones of huge mammals in the island of Kefallonia.

The first inhabitants of the island originate in the Prehistoric Era. Findings of the Neolithic period in Fiskardo, Mounda, Skala and Poro prove the existence of man in the caves of Kefalonia, in 50.000 B.C. These stone findings are, axes, knives, wedges, scrapers, punches, samples of the life of the human being back then. During that period, man used to live in nomads and fed himself by hunting animals. The identity of these first inhabitants is a mystery until today. The first known inhabitants were Tafia or Tilevoes. The first known settler, Tafios, who was the son of Poseidon, named the inhabitants, Tilevoes. Even today, the legend of Cephalus predominates; the name Kefallites was first used by Homer and refered to the subjects of Odysseus, while the name Kefalonia is used, in 5th century BC, by Herodotus in reference to the inhabitants of the peninsula of Paliki "Palees oi ek Kefalliniis."

It is said that it is the real Ithaca, but the researchers believe that it was the action base of Odysseus and not the Homeric Ithaca. During the ancient times, the island was divided in 4city- states: the state of Sami, Pali, Krani and Pronea. Thucydides, justifiably, characterized Kefalonia as "tetrapolin".

These states were administratively self-governed, something that is justified by the ruins of the fortresses, that were found in the above areas. The constitution of these cities was democracy, they had the "parliament" and the public, which were the administrative body, which used to take decisions on vital sociopolitical dilemmas.

The archaeologist N. Kyparissis, referring to the Cyclopean Walls and the walls of the ancient Krani, states that in these walls, one can observe all the stages of the historical development of the island , from the ancient times until the years of the Roman Empire, a period of 3.000 years. The island, according to the archaeological findings, flourished in the Mycenean period, 1500 BC and communicated with Ithaca, Lefkada and the islands of Cyclades. This communication ended after the explosion of the volcano of Santorini.

The island, in 394 - 1185, was one of the Ionian issues of the Byzantine Empire, the "Issue of Kefallinia", which helped to prevent the attacks of the Arabian pirates . From 1185 and for some time, the island was free and independent until 1195, when the island passed under the Venetian domination and the authority of Orsini.

In 1357, the island is dominated by Tokkos and in 1479 by Turks. The turkish domination lasted 17 years and it is divided in 2 periods, the first (1479- 1481) and the second (1485 - 1500). The turkish domination resulted in the decline of the island in many areas.

The Venetians, after 1500, tried to restore what the barbaric domination of the Ottomans had destroyed. In collaboration with the local people, they tried to reform culturally and administratively the physiognomy of the island. The fortress of Agios Georgios, until 1757, was the action base of the Venetians and the capital of the island for that time. The area finally flourished and wonderful churches were built, like the churches of Agia Paraskevi, Agion Theodoron, Evagelistrias and Agios Nikolaos, wonderful representatives of ecclesiastical architecture influenced by the Venetian art and the Italian renaissance.

The capital of the island, due to commercial advantages, was transferred, in 1757, to Argostoli, where it remains until today the largest city, port and touristic resort. The turning over of the island to the Venetians is represented in the painting of the Cretan painter Georgio Klonza, which is kept in the Markiani Library of Venice. Argostoli, the capital of the island, was govened by 17 Venetians, until Jacob Manin handed the island over to the French.

That time, existed the Council of the Committee, an administrative party, which was comprised of Aristocrats, who were registered in the great Gold Bible or "Libro d' oro", something that reminds the Old Parliament, which was in function in the island, some centuries ago. When the Venetians were in power, Kefallonites developed close and active relationships with wesrern countries, resulting in the infiltration and partial assimilation of spiritual and material values. The influence from the west in the island is obvious in the civilization and particularly in the education, since the youngs who were studying in Venice and Pizza used to bring liberal ideas to the island. This resulted in the social, spiritual and cultural reorganization and awakening of the inhabitants of the island.

The person that distinguished herself in the island, according to the historical researcher W. Miller, during the Venetian domination, is the Queen of Roman, Francesca, wife of Prince Charles A', known as "Francesca Dei Gratia Vasilissa Romeo rum" or as medieval Penelope. During the years of Roman Empire, lived in the island, exiled, Gaios, the brother of Marcus Antonios.

It was under the Venetian domination until 1797 and played an important part in the Mediterranean area, since it was the crossing point of the Venetian troops to the Middle East. The ports of Sami, Fiskardou and Atheva were refuge for the Venetian navy.

The accumulation of population in the Ionian Islands, mainly after the fall of Cyprus in 1570, the Cretan seizure in 1669 and part of south Peloponnese in 1718, lead to its spiritual and social change. After the collapse of the Venetian domination, the island passed to the democratic French, who controlled all the islands of the Ionian Sea.

During the years of French domination, the island organized the education and founded French speaking schools, a National Library and a printing-office. With anti-French uprisings, the island, in 1798, with the leaders Ousakof and Katir Bey, passes to Russian-Turkish domination. The inhabitants of the island, with delegates to Constantinople and Petroupoli, and with direct communication with the representatives of the other Ionian Islands, try to gain their official freedom and independence, something that they finally succeeded. So, in 1800, the treaty of Constantinople, establishes the Ionian Islands as a united state, the first independent greek state known as the "State of the Seven United Islands".

The Ionian State has its own Constitution and flag, however the uprisings and the continual troubles are still present. The people that stood out in these radical uprisings are, Hlias Zervos Iacovatos, Gerasimos Livadas and Iosif Momferatos. Moreover, intense political activity came from Typaldos Pretederis, Ioannis Menagias, Francesco Pylarinos and Stamatelos Pylarinos.

In an intense atmosphere of inner conflicts, the state of the Ionian Islands collapsed in 1807 by General Caisar Berthier; so the island, after the treaty of Titlist, passed to the French, for the second time. In 1809, and after the crushing of French powers, the island was seized by the English, with General Oswald in the lead. In the period between in 1810 - 1814 the island was govrned by Charles Philip De Bosset from Switzerland, who helped to reorganize the island; he opened roads, rebuilt destroyed buildings, built the famous bridge of Drapanou, and in general, he also tried, and partially succeeded, to improve the image of the island from the repeated conquests and attacks.

In the same pattern, followed Charles Jacob Napier, where, in his time, the famous Judicial building was built in Argostoli, the Customs office, the Lighthouse of Agion Theodoron and the Court building in Lixouri.

Despite the English domination in the island, the inhabitants of Kefalonia, like most of the inhabitants of the Ionian Islands, participated in the Independence War of 1821. Their participation was due to the effects of the French revolution, the western influences and the continuous socio-political changes in the island.

In 1823, in the years of the Greek revolution, Lord Byron was living in the island where he wrote "Don Juan"; he, then, went to fight in the besieged Mesologgi, where he died. Despite Greece's freedom from the Turkish yoke, the island was still in bondage. The historical revolts of 1848 and 1849 marked the history of the island.

Finally, the treaty of London, in 1863, allowed the union of the island with the rest of the Greek state and the destiny of the island is the same as the destiny of the Greek state, from 1864 and after. The resolution of London stated " The islands of Corfu, Kefalonia, Ithaca, Zakynthos, Lefkas, Kythera, Paxi are united with the Kingdom of Greece, and comprise an inseparable part of it, in one and indivisible State under the constitutional scepter of the King of Greece, George A' and his heirs. 

The political activities of the inhabitants of the Ionian Islands continued in the Greek state with the representation of socialism in it by Panagioti Pana, Rokko Hoida and Marino Antipa. In the new era, many buildings and monuments were destroyed by the earthquakes that followed; exception was the region of Fiskardo.