Back to the Future How medieval methods built a French castle today

It was the summer of 1999 and, in a disused quarry in a forest in deepest Burgundy, a dozen or so incongruously attired figures were toiling away, hewing limestone blocks, chiselling oaken beams and hammering 6in nails.

- Jon Henley

The rough outline of what they were building was discernible, just: a perimeter wall a substantial 200 metres (655ft) long and three metres thick; round towers, two large and two small, to mark the four corners; another pair flanking the main gateway.

Outside the clearing it was almost the 21st century. Inside, it was 1230 and, using only medieval tools and techniques, as well as materials sourced locally or made on site, work had just begun on the castle of Guilbert de Guédelon, also known as Guilbert Courtenay, a fictitious nobleman of relatively modest means.

Back then, the walls were half a metre high and no one had the faintest idea when - or, more to the point, whether - Château de Guédelon would ever be finished. No one, after all, had thought to build an early 13th-century castle by hand for about 750 years.

Just over a quarter of a century later, it still is not quite finished. But in the summer of 2025 it is, recognisably and rather splendidly, an early 13th-century French castle, complete with ramparts, turrets, vaulted great hall, chambers, chapel, kitchens and, a little way off in the woods, a working flour mill.

It is also a living archaeological, architectural, cultural, historical, human and even scientific laboratory, praised and prized by medievalists, heritage restoration experts and professionals in the sustainable construction industry.

“I’m not really sure what I thought would come of it. Back then, it sometimes felt like just… having fun with friends,” said Maryline Martin, Guédelon’s project manager since the start. “It’s been the most amazing adventure. And it’s worked in a way I never dreamed of.”