PICTURESQUE ruins near a remote village once housed the political powerhouse and religious capital of Wales, archaeologists have revealed.
Experts from the University of Wales, Lampeter, say the abbey at Strata Florida was once a city of light to rival Westminster Cathedral and Oxford.
Situated near Pontrhydfendigaid in rural Ceredigion, the abbey is now in ruins, providing the area with a place of outstanding beauty. There are rumours it once held the most sacred of all icons, the Holy Grail, but there were very few other clues as to its hugely important past.
Now work by archaeologists, led by Professor David Austin, has revealed the ruins were once 10 times the size they now appear. And deciphering names of farms over a wide radius has helped uncover the true scale of a massive monastic operation on the site hundreds of years ago.
The roots of the modern village of Pontrhydfendigaid are all down to the importance of Strata Florida, says Prof Austin, who has used aerial photographs, geophysics and excavation techniques to assist his work.
"People say that Strata Florida is the Westminster Abbey of Wales," he said.
"But one day I will stand in Westminster Abbey and say, 'Oh gosh, so this is the Strata Florida of England.'
"Comparing it to Westminster does give a good picture of its importance though."
Prof Austin believes the community was once home to at least 500 people at a time when the biggest walled cities in Wales probably only housed about 1000.
"Most people who currently visit Strata Florida go to the Cadw monument and see the ruins of the main church and some of the cloisters," he said.
"Any specialist would know that an abbey would be bigger than that, but what has surprised us is how big this once was. We now judge that the size of the site is spread out about three-quarters of a mile, stretching down the valley to the village of Pontrhydfendigaid.
"We think that the village was also set up by monks to provide a labour force for the abbey.
"And the abbey set up, for a five-mile radius, a very specialised farming operation, with a number of farms like Dol Efolion or Meadow of the Foals providing all their horses.
"We are very interested in how such a large operation would have worked."
He said the size of the site reveals why some of Wales's best known literary figures are buried there - medieval poets like Dafydd ap Gwilym making it the "Welsh Oxford" of the day.
"It would be going too far to describe it as a capital city but it was where all the thinking was going on in the middle ages.
"It was a centre of books, and Gerald of Wales complained that Strata Florida had stolen his books - he was very bitter about that."
And a centre of politicking, too, it seems.
Comparing it to Westminster helps explain why Welsh prince Llywelyn Fawr, who had all of the nation's other princes under his rule, chose Strata Florida for a major meeting place shortly before he died in 1236.
"He asked them that their loyalty be passed down to his son Dafydd when he died.
"Had that happened, Wales would have become a nation," said Prof Austin.
"So for some reason Strata Florida was very important."
As well as emphasising the importance of Strata Florida, Prof Austin wants to boost the area's tourism fortunes.
"Cultural tourism is an asset," he said.
As for interest in the Holy Grail, growing off the back of books like Dan Brown's The Da Vinci Code, Prof Austin said, "Whether true or not the power of the place is unquestionable.
"There is a real feeling of hiraeth that goes way beyond the cold monastic ruins that remain there today."