Blood and Mistletoe: a history of the Druids in Britain, By Ronald Hutton

Blood and Mistletoe is not so much a history of the Druids in Britain as a history of how the Druids have been endlessly re-visioned by people with different preconceptions, prejudices and agendas in the changing cultures of England, Scotland and Wales. Like much of Ronald Hutton's work, it is a study in reflexivity: "why it is that we see our subjects of study in the way in which we do".

Hutton is a professor of history at Bristol University, and Blood and Mistletoe is his second crack at this subject, a companion to The Druids. That was written for a popular market; this is academic and more than three times the length, though still very readable.

There is little raw material on the Druids, most from the classical histories of Julius Caesar, Strabo, Tacitus and Pliny. Some of this "may be wildly inaccurate and some accurate in the last detail"; without knowing their sources, there's no way of telling.

All we can know is that "the dualistic image of the Druid, at once wise and learned and a specialist in horrific acts of sacrifice, was standard among Greek and Roman writers by the first century CE." Wisdom and barbarism: the contrasting images of Druids through the centuries.

Oddly, the classic image of the long-bearded sage comes from a late-15th century German writer, despite there being no evidence of Druids in Germany. In the 16th century images (and imagination) about them passed from Germany to France to Scotland and then to England as part of nationalist history-writing.

Exploding a popular misconception, Hutton shows how "the Welsh came late to an incorporation of Druidry into their national self-image". When they did, in the late 18th century, it was through the "wayward genius" Iolo Morganwyg ("Glamorgan Eddie"), more prosaically known as the stonemason Edward Williams.

In the spirit of his near-contemporaries Chatterton and Macpherson, he inserted his own forged poems and invented descriptions of Druid ceremonies into his translations of mediaeval Welsh poetry, and largely got away with it. He also established the gorsedd, a ceremonial meeting of Druid bards at the eisteddfod, turning it from just a poetry festival into a Druidic event.

Hutton is particularly good at those little cameo details that stick in the mind. One of Iolo's successors wrote books on pagan religion; they are scarce because "chapel preachers... encouraged their flocks to buy them up and burn them". By the 1890s, the eisteddfodau were well established and impressive, and real stone circles were built for the ceremonies – as Hutton notes wryly, "probably the first megalithic structures ever erected by Druids".

We have a Druid to thank for crematoria. An elderly Druid doctor in Glamorgan, William Price, was arrested for attempting to burn the body of his baby son on a hilltop in 1884. He was acquitted on the grounds that there was no law specifically forbidding cremation – and within three months, the first public crematorium was being constructed in Britain.

Hutton covers a number of modern Druid Orders: the first, a philanthropic group of local worthies in Anglesey, founded in 1772. The Ancient Order of Druids, founded in a London pub in 1781, celebrated drinking and music; and the Druid Orders of the spiritual counter-culture began using Stonehenge for ceremonies in 1905, establishing a their perpetually turbulent relationship with the authorities there.

This book is a tour de force: surely the definitive work on our perception of the Druids. The only thing missing from this exhaustive account is an overview, however brief, of today's colourful Druid groups – an odd omission by the acknowledged historian of neo-Paganism. For that, you need his earlier book.

David V Barrett's 'The New Believers: sects, cults and alternative religions' is published by Cassell