First description of Britain

In 325 BC, his health already undermined by drink, wounds and malaria, Alexander the Great arrived back in Iran having touched the northern and eastern edges of the known world at the Caspian, the Syr Darya river and the Himalayan foothills.

That same year, perhaps, at the other end of the world, a lone navigator sailed out of the Pillars of Hercules into the ?Great Ocean?. A native of the Greek colony at Marseille, Pytheas the Greek embarked on an astonishing voyage of exploration, circumnavigating Britain, touching the Hebrides, Orkney, and Shetland, entering the Baltic, and incredibly, reaching the edge of the pack ice in the gloomy wastes beyond Iceland - Ultima Thule: a feat which must have appeared to the Greek mind little short of entering Hades itself.

It?s an amazing tale. So amazing, in fact, that many in the ancient world doubted that Pytheas had ever seen what he described. In Roman times, Pytheas?s book On the Ocean was lampooned as a fiction, a precursor of Mandeville?s travels. Pytheas himself was branded a liar just as Marco Polo would be. It is easy to see why. The unknown is often unbelievable, and some of Pytheas?s tales must have verged on the incredible to a Mediterranean audience, living, as they liked to say, ?like frogs around a frog pond?. Tidal races 100ft high, lands where the sun never set ? all this was mind-boggling. Especially improbable was Pytheas?s account of the vistas-beyond the last land ? Ultima Thule. There he says he saw the ?pnevmon?, literally, the ?lung? of the sea: a fantastic description of an eerie world where the sea congealed in an icy fog and metamorphosed into creaking fields of ice. It sounds straight out of Jules Verne, but it was all true.

Unfortunately, Pytheas?s book was lost at the end of the ancient world, and is known merely from quotes in later geographers. It is only in modern times that Pytheas has been rescued from the sneers of his detractors, and his adventure reinstated as one of the great voyages of discovery. It?s a tale Barry Cunliffe is supremely well qualified to tell. One of our most eminent archaeologists, his work has centred on the Iron Age in western Europe; that late-prehistoric world which the Greeks encountered in many places in the amazing epoch of their expansion across half of the known world.

Professor Cunliffe tells the tale as a detecanothertive story, whose evidence is drawn from the widest sources. Greek and Roman texts, sailing manuals, tide tables, even medieval chronicles which have passed down precious fragments of Pytheas?s memoir ? the first literary account of the British Isles. He is especially compelling when he shares his intuitive skills as an archaeologist, as, for example, when he judges the feel of a site, its life and contacts; peopling it with the farmers and merchants whose lives he has retrieved from the soil, and whom Pytheas actually met. He tells us, too, from first hand experience, what it is like to sail the dangerous coasts of Ushant, or the Western Isles; he knows the landfalls in Orkney and Shetland. From such converging clues he recovers the facts of a real voyage, whose clinching evidence is Pytheas?s key measurements of latitude, three of which, it turns out, were taken in Cornwall, on the Isle of Man and near Stornoway.

It?s a pity we don?t know more about Pytheas himself: he seems resourceful, curious, and open-minded ? one of the most attractive characteristics of Greeks of that age. It is especially tantalising that we lack more detail of his journeys inland, where he claims he spent a long time among the indigenous Britons, the Pretani, or ?painted people?.

So how did he do it? Professor Cunliffe thinks Pytheas travelled with local sailors on local boats, passed on from one community to and he gives us a feast of surprising detail on the ocean-going vessels which plied the Atlantic seaboard in the Iron Age. He may be right in this, but I wonder if it is not more likely that Pytheas sailed in a Greek merchantman ? the kind of boat which left the mysterious anchor stock raised in 1974 off the Llyn peninsula North Wales, and now in the National Museum in Cardiff ? I find it hard to imagine he managed all this without a boat of his own. If he did, he goes up even further in our estimation.

And a final question remains unanswered. Why did he do it? Was Pytheas operating as a lone merchant venturer? Was he simply driven by curiosity? Or was he acting on a Macedonian commission? That last possibility takes us back east. In June 323 BC, ravaged by drink and fever, Alexander lay sweating on his deathbed in Babylon. There were grandiose last plans, or so we are told: a huge new fleet; a road through North Africa to Gibraltar; the conquest of the West. ?Had he lived,? says the historian Arrian, ?he would not have stopped until he had subdued even the Britannic Islands to his rule.? It?s an unexpected detail, so late in the tale. Had Alexander already received Pytheas?s report on the ?Great Ocean? before his final illness? It is one of the many what-ifs raised by this fascinating book.

Michael Wood is the author of In the Footsteps of Alexander the Great