Scrabbling around on hands and knees in a muddy trench surrounded by the misty mountains of mid Wales may not be everyone’s idea of a fun way to while away the last days of summer.

But Julian Pitt, a former Royal Navy sailor still traumatised by his experiences in the Falklands and Gulf wars, was delighted to be sifting soil as part of the Strata Florida abbey archaeology project in the wilds of Ceredigion.

“It’s a funny thing,” he said. “When you’re out there working, you don’t think of anything else. It completely occupies your mind. You can’t be ruminating, you can’t be thinking ahead. You’re concentrating on the present moment. For me that is brilliant, just what I need.”

The Strata Florida project is one of the most intriguing digs in the UK. For starters, the site, 16 miles inland from Aberystwyth on the edge of the Cambrian mountains, has a fascinating and colourful history.

Though it is not very well known, even in Wales, there is growing evidence that Strata Florida was central to the development of the country’s culture and language.

Participants at the dig. Photograph: Dimitris Legakis/The Guardian

It features the remains of a sprawling Cistercian abbey founded in the 12th century and is the resting place both for medieval Welsh princes and possibly of the great 14th century Welsh poet Dafydd ap Gwilym, associations that have led to it being described as the Welsh Westminster Abbey.

Part of the Strata Florida (Latin for “Vale of Flowers”) site is managed by Cadw, the government body that looks after many historical sites across Wales, and it attracts a steady flow of visitors.

But over the last couple of decades archeologists have unearthed evidence that the site is vast, perhaps the largest Cistercian abbey in the UK, and has been a place of worship for thousands of years.

An organisation called the Strata Florida Trust has been set up to try to uncover more of the area’s amazing history and make people across Wales and further afield more aware of the site.

Prof David Austin at Strata Florida Abbey. Photograph: Dimitris Legakis/The Guardian

But the chair of the Strata Florida Trust, David Austin, who has worked on the site for decades, said there were challenges – in particular the size of the site and the shortage of field archeologists to uncover its secrets.

Rather than giving up, the trust – which is supported by the The Prince’s Foundation and the Allchurches Trust – has worked hard to recruit non-professionals to help the dig and the project’s first archaeology field school began this week.

“It’s such an important site,” said Austin. “Topographically, spiritually and intellectually it is at the heart of Wales. There is a growing understanding of the site and we have to get it out there. One of the ways of doing that is to get it to emerge out of the ground – magic it back up – and the archaeology sort of does that.”

Military veterans such as Pitt have been among the first to sign up for the summer field school at the site. Pitt said he had been unable to hold down a job for several years but being in a group was boosting his confidence and sense of self-worth. “It’s good being back working with people again,” he said.

Jilly Dawson and other archaeology workers. Photograph: Dimitris Legakis/The Guardian

Helping out at the school was the former marine Dickie Bennett, of Breaking Ground Heritage. He said many skills learned in the forces were transferable to the field of archaeology, such as attention to detail, the ability to work in remote areas in harsh conditions and to be part of a team.

Others who have suffered mental health issues have signed up including Brian White, a 53-year-old mature student who arrived on site with his therapeutic rabbit Pippin. “It’s wonderful to spend time with people with the same interests,” he said. “You are not judged, you just work together with all sorts of people.”

Also taking part in the first summer school include a father and daughter, husband and wife, a man on a mobility scooter and a young woman from Taiwan. It is giving people new to archaeology a taste of the subject. Jilly Dawson, 79, had wanted to be an archaeologist when she was a girl. “But nobody took the slightest notice of that wish,” she said. “I did what was expected. I got married and got a little job. It’s lovely to be here now – even if it is hard work and the weather isn’t always great.”