Book Of A Lifetime: The Pursuit Of The Millennium, By Norman Cohn

One year, my mother inherited £500. This was a princely sum. My parents put the money towards a tiny, flint-faced cottage on the Kent coast. Their hope, a regular injection of sea air into the lungs of our urban childhood. And indeed religiously, every holiday and half-term, we would wind our way down (fewer motorways then) to the seaside town of Hythe.

The routine was simple. Long walks to the fishing beach, illicit trespasses with knee-high boyfriends onto the nearby firing range, icy dips in the Channel, wrap up warm, then read by the fire or al fresco. I must have made it through well over 500 books on that stony stretch of coastline. The view was British down to the last cast-iron lamp-post and Cornish-wafer ice-cream, but the miles I covered in my head stretched beyond thousands.

When I was 15, I borrowed (permanently) from the school library a disintegrating copy of Norman Cohn's The Pursuit of the Millennium. I'd never gone abroad, but Cohn's tightly printed pages sang of an exotic European world. This was a history book – of the best kind. Investigating the Millenarian fantasies of the Middle Ages, Cohn uncovered a landscape where emotion and attitude were more powerful than high politics.

I devoured the tales of flagellants and choreomaniacs, who whipped or sang themselves into frenzies of eschatological expectation. The primary sources, scattered through the pages, short-circuited me back into the everydays of these wild, radical medieval men and women whose lives seemed to catapult between intense joy and the deepest despair.

Many of the Millenarians - eagerly anticipating the Second Coming of Christ, which would herald paradise on earth - made hard pilgrimages through Europe in search of salvation. By the end of the book I felt as though I knew every bush, every dirt-track, every venal ecclesiastical institution that they had passed.

Then and there I resolved to travel in their footsteps. History was something I knew as words on a page. Cohn's writing was so vivid, his research so original, I had an epiphany. The best way to respect these long-dead agitators would be to attempt to understand their existences under the same skies that they had known. The following year I managed to wangle an invite to Italy. My purpose was single-minded, to journey alone and travel in history's path. Every year after I ticked off the locations – Bohemia, Romania, Hungary, Germany. I owe an enormous debt of gratitude to Cohn. His writing taught me to leave the pen still, and go to experience the past as a present lived, not as an archival resource. Just before he died I had the chance to interview him. I drove down to his home, deep in the English countryside, and we sat under an apple tree, his long white beard wagging like one of the sages of his books, discussing the merits of making contact with others across time and space. I've rarely been happier.

Bettany Hughes's 'The Hemlock Cup: Socrates, Athens and the Search for the Good Life' is published by Jonathan Cape