Hidden Roman Fort Revives a Welsh Emperor’s Legend

On a clear morning, Frenni Fawr looks like nothing more than a quiet green shoulder of the Preseli Hills, the last high ground before the land rolls down toward Cardigan Bay. For centuries, locals have told two very different stories about it. One says a Roman emperor once pitched his tent on its summit while chasing a woman he had seen only in a dream. The other says a shepherd boy watched the fairy folk dance there and lost himself inside their golden palace.

This month, the first story picked up something it never had before: a Roman fort in the dirt. The Frenni Fawr Roman fort, identified by an Oxford archaeologist and dug with help from crowdfunding, is now being pitched as the camp behind one of Wales’s oldest legends. The evidence is real. What it proves is a different question.

The Frenni Fawr Roman Fort: What Was Found

Mark Merrony, a Roman specialist affiliated with the University of Oxford, first spotted the site in 2024. According to Smithsonian Magazine’s account of the dig, he was cycling through north Pembrokeshire when he noticed a triangular piece of stone in the ground that looked like a Roman roofing slate. Other reports say he had already picked out an outline in satellite imagery of an overgrown field.

Early work suggests an enclosure of up to three hectares, roughly 590 by 490 feet, about two miles southwest of the summit. That is large enough for a garrison of around 500 troops. Its rounded corners and road layout match other Roman auxiliary forts.

The finds read like a soldier’s junk drawer: fourth-century coins, an iron stylus for writing on wax tablets, a game piece, pottery shards, roof tile fragments, a spindle whorl, a kiln, clay floor bases and wagon-wheel ruts. A geophysical survey showed the outlines of two large buildings that Merrony believes may be a headquarters and a commander’s house.

Merrony plans more digs and says he will publish his findings in the archaeology magazine Antiqvvs. Until then, the fort’s details rest on early, unpublished fieldwork.

The Emperor Who Dreamed of a Welsh Princess

Magnus Maximus was a real man. He was a Spanish-born general serving in Britain when his troops proclaimed him emperor of the West in 383. He crossed to the continent, ruled for five years and was defeated by the eastern emperor Theodosius I. He was executed in 388.

Wales never let him go. In Welsh tradition he became Macsen Wledig, and centuries later the chronicler Geoffrey of Monmouth turned him into a king of Britain who married a Welsh princess.

The most famous version is “The Dream of Maxen Wledig” in Lady Charlotte Guest’s Mabinogion translation. In it, the emperor falls asleep during a hunt and dreams of a journey across mountains and sea to a castle where a maiden waits. He wakes lovesick. His messengers trace the landmarks of the dream to Britain, where they find her. Her name is Elen.

Maxen sails to Britain, wins her and marries her. Elen asks for castles and has great roads built between them, roads the tale says still bear her name. Then, during a hunt, the emperor climbs a high hill and pitches his tent at the top. The place, the story says, is still called Cadair Maxen, Maxen’s Chair.

Why the Hill Matters to the Legend

Merrony and the reports on his work identify that hilltop camp with Frenni Fawr, the easternmost high point of the Preselis. Before this fort turned up, nobody had found Roman military remains anywhere near the hill, so the camp story sat in the realm of folklore.

Merrony’s argument is simple. An emperor does not camp alone in hostile country. “If Magnus Maximus was there, there must have been an army there,” he told reporters. A fort holding 500 soldiers within sight of the summit is exactly the kind of base that would support a commander in the field.

He does not claim Maximus built it. Smithsonian reports that Merrony dates the fort’s construction to the governorship of Sextus Julius Frontinus, between 74 and 78 C.E., during the Roman push into Wales. The fourth-century coins suggest the site still saw use, or at least visitors, in Maximus’s era.

The fort also challenges a long-held view of the region. In a 2024 note from Oxford’s Wolfson College, Merrony said it suggests the Romans came down hard on the local Demetae tribe rather than living alongside them peacefully.

The Fairies of Frennifawr

Here is where the hill gets stranger. Frenni Fawr is also home to one of the best-known fairy stories in Welsh folklore, first printed by William Howells in Cambrian Superstitions in 1831 and later retold by Wirt Sikes in British Goblins in 1880.

Local weather lore held that if the morning fog on Frenni Fawr drifted toward Pembrokeshire, the day would be fair. If it drifted toward Cardigan, rain was coming. One June morning, a shepherd boy of about twelve looked up to check the fog and saw what he first took for soldiers on the summit.

They were too small to be men. They were the Tylwyth Teg, the fair folk, dancing in a ring. The men wore red caps. The women rode small white horses. When the boy stepped into the circle, he found himself in a palace of gold and pearls, fed and entertained, with a single rule: never drink from a certain well in the garden.

He drank anyway. The palace vanished, and he was back on the hillside with his sheep. He felt he had been gone for years. Only minutes had passed, a reversal of the usual Welsh fairy tale, where a few minutes with the fairies turn out to be a lifetime.

A Hill Full of Old Secrets

Frenni Fawr sits in a landscape that has earned its reputation for mystery. Ancient burial cairns crown its summit. Farther west, on the northern slopes of the same hills, lie the outcrops that supplied Stonehenge.

Researchers led by Mike Parker Pearson of University College London traced Stonehenge’s bluestones to quarries at Carn Goedog and Craig Rhos-y-felin and dated quarrying there to around 3000 B.C., as the University of Southampton reported. That stone traveled nearly 180 miles to Salisbury Plain, and exactly how is still argued over.

Readers who followed our recent look at a bronze ring tied to the lost Lighthouse of Alexandria will recognize the pattern. A single object or ruin can reopen a story that scholars had filed under legend. More of these finds live in our Supernatural Mysteries and Ancient Secrets section.

What Skeptics Say

The strongest objection is about time. The Mabinogion tales survive in 14th-century Welsh manuscripts such as the Red Book of Hergest, roughly a thousand years after Maximus died. Medieval storytellers routinely attached famous names to local landmarks. A tale that says an emperor camped on a hill is evidence of what medieval Welsh people believed, not a field report.

The place name is not as clean as it sounds, either. Lady Guest’s translation renders the hill as “Brevi Vawr” and places the hunt near Carmarthen, where the tale says Maxen then built a castle. Reading that hill as Frenni Fawr is an interpretation, one that Merrony’s camp supports but that other readers of the text may not share.

Then there is the fort itself. If Merrony’s dating holds, Roman soldiers built it some 300 years before Maximus took power. A handful of fourth-century coins shows late Roman activity, but coins move around, and none of the reported finds names Maximus or shows a major army in the 380s. So far, the work has not been through peer review.

The fairy story has an ordinary explanation too. The boy saw small figures in the mountain fog at dawn. The Met Office explains the Brocken spectre, an effect in which a person’s shadow is thrown onto mist, distorted by water droplets and made to look like a giant or distant figure that moves as the cloud shifts. Hill fog has fooled walkers for centuries. Add a tired child, a long morning and a culture rich in fairy lore, and the tale needs no magic at all.

Folklorists also note that the story’s plot, a forbidden well and a vanishing palace, follows a template told across Wales and beyond. That points to a shared storytelling tradition rather than a single real encounter.

Why It Matters

Stories like this grip people because they promise that legends are not just made up. Most of the time, the evidence lands in between. The fort is real. The emperor was real. The dream, the princess and the fairies belong to the people who kept telling the story long after Rome left.

That middle ground is where the best history lives. It is the same lesson behind the cold case at Iraq’s Shanidar Cave, which we covered in our report on a possible Neanderthal spear wound. Physical evidence can sharpen an old story without settling it.

For the Welsh, Macsen Wledig is more than a footnote. He stands as the figure who marked the turn from Roman Britain to a Welsh nation telling its own story. If more digs on Frenni Fawr tie the fort to the late fourth century, it would put real soldiers and real boots under one of that nation’s founding myths.