It’s 1200BC, and after 10 years of war the Trojans have been vanquished. Helen’s catastrophic flirtation with Paris has come to an abrupt end and she is now playing the dutiful housewife with her husband, Menelaus, back in Sparta. Meanwhile, Agamemnon, the Greek commander, has returned to Mycenae only to be murdered by his adulterous wife, Clytemnestra. But what of Odysseus, master of plots and teller of tall tales? How is he to explain to his faithful wife, Penelope, that instead of spending just a week or two on the voyage home from Troy, it has taken him another 10 years to return to his palace on Ithaca?

It wasn’t because he left his sat nav behind.

Odysseus is literature’s most famous philanderer: he hardly has to set foot on a deserted island before its resident goddess summons him to her bed. Circe transforms his shipmates into pigs, and only by withholding the comforts of the couch does Odysseus persuade her to undo her magic. Calypso is so besotted that she offers him the gift of immortality if he will agree to pleasure her — for ever. It takes a personal message from Zeus to free him from her embrace and to bring him back to his homeland in western Greece.

Corfu, Lefkas, Cephalonia, Ithaca, Zakynthos... the islands Odysseus lingered on are still there, but our journey to reach them is a little swifter than his. The flight from Gatwick takes you over Venice and down the eastern coast of Italy, and after just three hours, you’re fastening your seat belt for the descent into Argostoli airport. This is the small capital town of Cephalonia, devastated by an earthquake in 1953 and later immortalised in Captain Corelli’s Mandolin. But behind those beautiful beaches and majestic mountains, there lies a mystery that is more than 3,000 years old: to which of these islands did Odysseus return from his fabulous adventures?

Homer seems to spell it out for us. Odysseus is on an island called Scheria, which is thought to have been Corfu. He is speaking of his homeland to its king, Alcinoos, and he describes it as follows:

I am Odysseus, Laertes’ son, world-famed For stratagems: my name has reached the heavens. Bright Ithaca is my home: it has a mountain, Leaf-quivering Neriton, far visible. Around are many islands, close to each other, Doulichion and Same and wooded Zacynthos. Ithaca itself lies low, furthest to sea Towards dusk; the rest, apart, face dawn and sun. Odyssey 9.1926

So where’s the problem? After all, today’s island of Ithaca has long been regarded as Homer’s Ithaca: it even offers day trips to landmarks listed in the Odyssey. But what about those last two lines, which describe Homer’s Ithaca as lowlying and furthest out to sea towards dusk — ie to the west? How can we make any sense of that as a description of Ithaca, which is mountainous and lies to the east of Cephalonia, towards the mainland of Greece?

Did Homer simply get it wrong? That has been the reluctant conclusion of most scholars over the ages. But in 2003, a radical alternative was proposed. Could it be instead that geological changes in this earthquake-afflicted terrain have altered the landscape since the Odyssey was composed? Could the western peninsula of Cephalonia, which is today called Paliki, once have been an independent island, separated from the rest by a narrow sea channel? Because if it was, then Homer’s Ithaca was not today’s island called Ithaca at all. It was instead Paliki, which is indeed lowlying, furthest out to sea and facing towards the western dusk — just as the poet described it.

OUR GUIDE, Pavlos Georgilas, has taken us to the northern end of this ancient sea channel, to a bay called Agia Kiriaki. It is late August but we have the place to ourselves. Things change slowly here: the family who run the fish restaurant, the Apergis, have lived here since parish records listed their name in 1264AD, and perhaps for long before that. Along the beach to the east is a wall that is being excavated every winter by the waves: its style has been diagnosed as Mycenaean, the period of Odysseus. We help Pavlos to unload the sea kayaks off the trailer and he gives us a briefing: none of us has done a trip like this before.

Before we know it, we are in the water and paddling past the jetty into the open sea. A light swell, brilliant sunshine, an open sky. I have sold this outing to my son Mark, 13, as a tough adventure and now he is battling with the reality in the front seat of our canoe. It’s not that the paddling is difficult: it’s simply that we have another seven hours in front of us and eight more miles to go. But the magic has already begun, because if the theory is right, then we are retracing the route by which the shipmates of Odysseus’s son, Telemachus, evaded a watery death on his return from mainland Pylos.

While her husband was away, suitors wooed Penelope, intent on seizing the crown of Ithaca: but first they needed to dispose of the young prince and his inconvenient claim to the throne. To escape from their ambush, Telemachus disembarked on the western coast of Paliki while his crewmen sailed round to Agia Kiriaki and the narrow sea channel to the south. That took them precisely along our route, but in the opposite direction.

We gaze up at the sheer cliffs, at the landslides that have catapulted countless tons of limestone into the ocean. Was this the view that greeted those sailors more than 3,000 years ago?

Great flocks of sea birds swoop and dive in our wake, and as we round Agiannis Point, we are greeted by a deserted beach to die for. We swim, but it’s not yet time for lunch. We paddle on with Pavlos and Lee, an expatriate Brit who has seen the light of Greece and can never work in an office again.

Poseidon the earth-holder is relentless In anger for the son Odysseus blinded, The godlike Polyphemos, mightiest Of Cyclopses. His mother was the nymph Thoosa, daughter of the sea-god Phorcys, Who mated with Poseidon in a cave. The earth-shaker does not wish to kill Odysseus, But keeps him wandering far away from home. Odyssey 1.6875

THE CAVE appears slowly from across the sea, like the entrance to an alpine tunnel. We draw closer and now we are dwarfed at its mouth. Inside, the waves beat against its jaws and the suction bares its gums. Pavlos kayaks in and we follow. We paddle against the swell and twist around to face the opening. This sea space is vaulted like a church: Poseidon could well have had his watery way in here with Thoosa. Is that why he was called the “earth-shaker”: did the earth move for her?

We lunch at a bay inaccessible by foot. Then we canoe past wild headlands convulsed by geological upthrusts. This is the most tectonically active landscape in Europe: only 12 miles to the west, the seabed drops from 300 to 3,000 metres. If you drained the sea, you would find yourself standing at the edge of the African continental plate, while in front of you the cliffs of Europe rear up — and they are two miles high. That is why Cephalonia experiences so many earthquakes, because the African plate is pushing it up like a springboard, and this island is at its tip. Homer was not fanciful in his description of Poseidon: the earth-shaker remains with us today.

We are five hours into the trip and I’m starting to realise that exercise matters. The experts are gliding along effortlessly, but we have rounded the northern point of Kakatos and now the wind and the currents are working against us. To the west, past the next headland, there is nothing but open ocean for 200 miles until the toe of Italy: enough reach for a serious swell. But we are at last on the course that Odysseus took on his final journey home:

As soon as that most brilliant star arose Which is sole herald of the light of dawn, Then the seafaring ship approached the island. On Ithaca there is a bay of Phorcys, The old man of the sea: in it, two headlands, Projecting, sheared off, crouching from the harbour, Shield it from waves whipped up by blustering winds Outside... They rowed inside: they knew the bay of old. The ship ran up the beach for half its length At speed: such strength was in the rowers’ arms. Odyssey 13.93115

Odysseus is asleep and the crewmen are bringing him back on a direct route from Corfu. Their landfall is today called Atheras Bay. Homer’s description is exact, and this landscape matches it exactly. We pass the outer headlands to find two inner ones that are “in” the harbour, just as the poet observed them. The rough waters are behind us: this bay is well shielded from the waves. On the final stretch, we accelerate and run the kayaks up the beach for half their length. Yvonne waits for us in the Land Rover like the patient Penelope. She is greatly welcome, and so is the simple meal that greets us there. We have followed Odysseus across the sea, and now we match his footsteps on the land. He has returned at last to Ithaca. He sleeps on through the night, and so shall we.

Travel brief

Getting there: Cephalonia is served by charter flights from seven UK airports, with fares from about £200. Book through Excel (0870 320 7777, www.xl.com), Thomson (0870 190 0737, www.thomsonfly.com) or First Choice (0870 850 3999, www.firstchoice.co.uk). Alternatively, Olympic Airlines (0870 606 0460, www.olympicairlines.com) has fares year-round from Heathrow from £250, via Athens.

Where to stay: the Paliki peninsula is much quieter than the main tourist areas of Cephalonia. The aptly named Odyssey Villas has low-cost rooms in beautiful but remote Agia Kiriaki (00 30-26710 85076, www.ionion.com/odysseyvillas; doubles from £xx), while, for the well-heeled, the Emelisse Hotel (26740 41200, www.arthotel.gr/emelisse; doubles from £xx) in Fiskardo provides luxury and a breathtaking view.

Sea kayaking: Monte Nero Activities (69329 04360, www.monte-nero-activities.com) provides a range of marine adventures, from a single day’s outing to a week’s kayaking between different islands. Day trips run from £35, while a nine-day tour around the Ionian Sea costs from £650, including accommodation (often camping) and most meals.

Odysseus Unbound: The Search for Homer’s Ithaca by Robert Bittlestone, James Diggle and John Underhill is published by Cambridge University Press at £25. Extracts are available at www.odysseus-unbound.org

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