Shadows of dead men's markers

The distinguished archaeologist Charles Thomas has published a prolific succession of books and articles elucidating that eternally fascinating era customarily known as the Dark Ages. It is a period whose evaluation requires an exceptional variety of skills, straddling as it does fields of expertise, such as history, archaeology, epigraphy, and philology. Two mysterious centuries lie between the end of the Roman dominion over Britain at the beginning of the 5th century ad and the early decades of the 7th century, when Bede's great history begins to throw an acceptable light on men and events.

During those two centuries the voices of two Britons alone speak to us with contemporary voices, affording tantalising glimpses of a period otherwise mantled in obscurity. Saint Patrick, who was born somewhere in western Britain in the 4th or 5th century, wrote a moving apologia for his missionary activities in Ireland, and a subsequent letter of protest to a predatory British king Coroticus, who had abducted and enslaved many of Patrick's converts. Gildas, a British priest or monk, lived about the middle of the 6th century. His potted history of Britain tells us little of value, since it is almost entirely drawn from known Roman sources. However, when he describes events of his own and his parents' day his account carries credence, and his excoriation of five allegedly lascivious kings reigning in western Britain affords a unique glimpse of the contemporary social and political scene.

Apart from these two chinks in the darkness, there is little else that can be asserted with confidence of historical events in these two missing centuries. The void is especially frustrating, as it is a period of unique significance in the history of this island. Between 400 ad and 600 ad the inhabitants of what is now England became predominantly English-speaking. The British and Latin languages perished as living tongues, and Britain remains unique as the only former European province of the Roman Empire not to speak a romance language. Similarly Anglo-Saxon law was unique among barbarian codes in owing little to Roman law.

This was the period, too, when the Britons of the west and later the English became converted to Christianity. Still more evocatively, it was the era to which bards and chroniclers ascribed the reign of Arthur, who defeated the heathen invaders in 12 great battles and reigned in glory as a model for all future kings. In his widely-read work The Age of Arthur, the late John Morris coincidently filled more than 600 pages with a blow-by-blow account of Dark Age history, in which he pressed into service medieval saints' lives, translations of early Welsh poetry and prose, and medieval chronicles, together with recent archaeological findings. Regrettably little of Morris's stirring narrative stands up to critical examination. The sources upon which he relied are for the most part far removed from the events they describe, whose authors frequently possessed no more reliable knowledge of events in the 5th and 6th centuries than do we. The current orthodoxy holds that, apart from the writings of Patrick and Gildas, all that is related of early Britain is seen through the hopelessly distorting lens of heroic legend and hagiographical folklore.

Never one to shun controversy, Thomas now presents a powerful argument for the possibility of extracting a coherent history from this multifarious range of evidence. His mastery of his own discipline is indisputable, and he has in addition mastered recent findings in epigraphy, source-criticism, and place-name studies. In particular he emphasises a neglected written record of undoubted contemporaneity. These are the standing stones - "the graves which the rain wets" - found on windswept moors and in lonely churchyards across Wales and the West Country, which bear epitaphs inscribed in Latin script or the ogham alphabet, the latter invented by an unknown Irishman living at the time of the Roman occupation of Britain.

Thomas also makes skilful use of a group of medieval records known as the "Brychan documents" after the eponymous founder of the kingdom of Brecknock, which he persuasively contends derive from a 6th-century corpus of court records. And Shall These Mute Stones Speak? is a fascinating detective story, whose arguments are at once imaginative and coherent, which in their essentials carry conviction. It is hard to think of a more perfect companion for a holiday in western Britain, whose enigmatic landscape is vividly brought to life in this major contribution to early medieval studies.

Nikolai Tolstoy is a historian and biographer.