Anglesey Sacred Isle

The Island of the Practitioners

In 60 AD, the Roman governor Suetonius Paulinus stood on the shore of the Menai Strait and looked across at Anglesey. On the far bank, according to Tacitus, practitioners stood among their sacred groves, raising their hands to the sky and calling down curses on the invading legions. Women in black robes, "like Furies, with their hair hanging down and carrying torches," ran among the ranks. The Roman soldiers hesitated — momentarily paralysed by the spectacle — before crossing the strait, destroying the groves, and slaughtering the practitioners.

Whether Tacitus's account is accurate in its details is debatable. What is certain is that Anglesey — Mona, the Romans called it, Ynys Môn in Welsh — was a place of exceptional sacred significance in the pre-Roman Celtic world. The island's concentration of prehistoric monuments, holy wells, and early Christian sites suggests a continuity of spiritual importance that predates the Romans by thousands of years and postdates them by two millennia.

This trail crosses Anglesey from its Neolithic passage tombs and burial chambers to the medieval holy well of St Winefride on the mainland shore, tracing the island's sacred history from the builders of Bryn Celli Ddu through the practitioners who defied Rome to the Christian pilgrims who followed in their wake.

Bryn Celli Ddu

On the southern side of Anglesey, in flat farmland near the village of Llanddaniel Fab, a low green mound marks the entrance to Bryn Celli Ddu — the "Mound in the Dark Grove." It is a Neolithic passage tomb, built around 3000 BCE, and it is one of the most important prehistoric monuments in Wales.

The tomb's significance lies in its alignment: the passage is oriented to the northeast, and on the morning of the summer solstice, sunlight enters the passage and illuminates the back wall of the burial chamber. The alignment is precise — the first light of the longest day travels 8 metres down the passage and touches the back stone for approximately twenty minutes. This solstice alignment connects Bryn Celli Ddu to a tradition of passage tomb astronomy that spans the Atlantic seaboard of Europe: Newgrange in Ireland (winter solstice), Maeshowe in Orkney (winter solstice), and the Clava Cairns in Inverness-shire (winter solstice) all share the principle of aligning a passage to capture specific astronomical events.

But Bryn Celli Ddu's story is more complex than a simple passage tomb. Before the tomb was built, the site was a henge — a circular ditch with a ring of standing stones. The tomb was inserted into the centre of the henge, its passage cutting through the earlier ditch. One of the henge's standing stones, a pillar carved with sinuous serpentine patterns, was buried within the tomb's mound. A replica now stands at the site; the original is in the National Museum of Wales in Cardiff.

This sequence — henge replaced by tomb, standing stone buried within the mound — suggests a deliberate act of transformation: the earlier ceremonial site was not abandoned but reimagined, its sacred materials incorporated into a new structure. The pattern echoes what we see at other sites across Britain: landscapes are not built from scratch but layered, each generation inheriting and transforming the work of the last.

The tomb is freely accessible. You enter through the passage — low enough to require stooping — and emerge in a central chamber roughly 2.5 metres in diameter, roofed by a corbelled ceiling. A single freestanding pillar stands at the centre of the chamber, smooth and rounded, its purpose unknown. Behind the chamber, a reconstructed mound passage leads to the rear of the monument. The whole structure is modest in size but refined in execution: the dry-stone walling is careful, the passage is straight, and the chamber feels deliberate — a space designed for a specific purpose, even if that purpose is no longer fully understood.

Barclodiad y Gawres

On the west coast of Anglesey, overlooking the sea at Cable Bay near Rhosneigr, Barclodiad y Gawres — "the Giantess's Apronful" — is a passage grave of extraordinary significance. The tomb contains carved stones: five decorated slabs bearing spirals, zigzags, chevrons, and lozenges, pecked into the rock surface with stone tools. This passage grave art connects Anglesey to the great Irish tradition of megalithic art at Newgrange, Knowth, and Loughcrew — and confirms that the communities on either side of the Irish Sea shared a common symbolic vocabulary.

The tomb was built around 2500 BCE and consists of a cruciform passage and chamber — a central space with three side cells, comparable in plan to Newgrange though much smaller in scale. The passage runs roughly south-southeast, and the carved stones are positioned within the chamber and at key points along the passage, their decorated faces turned inward toward the space used by the dead.

Barclodiad y Gawres is not freely accessible — the chamber is locked and visits must be arranged in advance through Cadw (the Welsh Government's historic environment service). This restriction, while inconvenient, has preserved the carved stones in exceptional condition: the spirals and zigzags are sharp and clear, their surfaces protected from weather and vandalism.

The connection to Bryn Celli Ddu is both geographical and cultural. The two tombs sit on opposite sides of Anglesey — Bryn Celli Ddu on the southern farmland, Barclodiad y Gawres on the western coast — and they represent two facets of the same Neolithic tradition: solstice alignment at Bryn Celli Ddu, passage grave art at Barclodiad y Gawres. Together, they demonstrate that Anglesey's Neolithic communities were fully connected to the wider world of Atlantic Europe — exchanging ideas, techniques, and beliefs with the communities of Ireland, Orkney, and the British mainland.

Bodowyr Burial Chamber

In a field near the village of Llangaffo, the Bodowyr burial chamber is a simple but elegant monument: a capstone supported by three uprights, creating a small chamber open on one side. It is what remains after the earthen mound that once covered it has eroded away — the skeleton of a Neolithic tomb, reduced to its essential geometry.

Bodowyr is small and unenclosed — you walk across the field and find it sitting among the grass, unprotected and uninterpreted. There is no visitor centre, no information panel, no car park. The monument relies entirely on its own presence to communicate its significance. This directness is part of Anglesey's character: the island's prehistoric sites are not mediated by heritage infrastructure but encountered raw, in the landscape, on the visitor's own terms.

Lligwy Burial Chamber

On the northeast coast of Anglesey, near Moelfre, Lligwy burial chamber is one of the most impressive late Neolithic tombs in Wales. Its capstone — a single slab of limestone estimated to weigh 25 tonnes — rests on eight low uprights, creating a chamber roughly 2 metres high and spacious enough for several people to stand inside. When it was excavated in 1909, the remains of between 15 and 30 individuals were found within, along with pottery, bone tools, animal bones, and shell fragments dating to the late Neolithic and early Bronze Age.

The sheer mass of the capstone at Lligwy demands attention. Moving a 25-tonne stone — even the short distance from a quarry outcrop to the tomb site — required coordination, planning, and significant communal labour. The effort invested in this single element speaks to the importance of the burial rite: the dead were housed beneath a stone of such weight that it would endure for millennia. And it has. The capstone at Lligwy has sat on its uprights for roughly four and a half thousand years, unmoved by weather, farming, or development. It is one of the most permanent things that any human community has ever made.

Lligwy sits within a landscape of other ancient sites: the remains of a Romano-British settlement (Din Lligwy) and a twelfth-century chapel (Capel Lligwy) are both within walking distance, creating a small cluster that spans three thousand years of Anglesey's history. The proximity of Neolithic tomb, Roman settlement, and medieval chapel on a single headland encapsulates the island's character: layer upon layer of human activity, each generation building on the sacred and strategic geography that the last one identified.

St Winefride's Well

Across the Menai Strait, on the mainland at Holywell in Flintshire, St Winefride's Well is the oldest continuous pilgrimage site in Britain. The well has been visited for healing and devotion since at least the seventh century AD — and possibly much earlier, given the pre-Christian veneration of sacred springs throughout the Celtic world.

The legend of St Winefride (Gwenfrewi in Welsh) is vivid: a seventh-century noblewoman, she was beheaded by a rejected suitor, Prince Caradoc. Where her head struck the ground, a spring burst forth. Her uncle, Saint Beuno, replaced her head and restored her to life. She went on to lead a monastic community and was venerated as a saint. The well's water, flowing at a constant rate and temperature from its deep limestone source, was attributed with healing powers, and pilgrims have come to bathe in its waters for over thirteen hundred years.

The well is housed in a remarkable Gothic chapel, built around 1500 by Margaret Beaufort, mother of Henry VII, over the actual spring. The bathing pool — a rectangular basin fed by the well — is still used by pilgrims today. The water is clear and cold, and the experience of entering it is bracing and immediate. Above the pool, the chapel's vaulted ceiling is carved with bosses depicting Winefride's story and the arms of the Tudor dynasty.

St Winefride's Well connects Anglesey's prehistoric sacred landscape to the living tradition of pilgrimage in the Celtic world. The well is on the mainland, a short journey from Anglesey, and it represents the Christianisation of the spring-worship tradition that the practitioners and their Neolithic predecessors practised. The water is the common thread: from the springs and rivers that the Neolithic tomb-builders aligned their monuments to, through the holy wells venerated by the practitioners, to the Christian healing springs that drew medieval pilgrims across Europe. The water has never stopped flowing.

Tinkinswood

Though technically in the Vale of Glamorgan rather than on Anglesey itself, Tinkinswood burial chamber is included in this trail as a counterpart to the island's tombs — a south Wales chambered tomb that belongs to the same Severn-Cotswold tradition as the Anglesey chambers and demonstrates the connections across the whole of Wales.

Tinkinswood's capstone is one of the largest in Europe: a single slab of limestone estimated at 40 tonnes, supported by several uprights and covering a rectangular chamber. The barrow mound, partially restored, stretches behind the chamber in a long trapezoidal shape. When excavated, the remains of at least 50 individuals were found within — one of the highest burial counts from any British Neolithic tomb.

The Sacred Isle

Anglesey's concentration of prehistoric monuments, combined with Tacitus's account of the practitioner stronghold, creates a picture of an island that was sacred long before recorded history. The passage tombs aligned to the solstice, the carved stones echoing Irish megalithic art, the burial chambers with their massive capstones — all speak of communities who invested enormous effort in the relationship between the living and the dead, between this world and the next.

The recommended sequence:

1. Bryn Celli Ddu — Begin at the solstice tomb. Enter the passage. Stand in the chamber with its mysterious central pillar.
2. Barclodiad y Gawres — Drive west. Arrange access in advance. See the carved stones.
3. Bodowyr — Drive to Llangaffo. Find the chamber in the field.
4. Lligwy — Drive northeast. Stand under the 25-tonne capstone.
5. St Winefride's Well — Cross to the mainland. Bathe in the spring.
6. Tinkinswood — Drive south to the Vale of Glamorgan. See the 40-tonne capstone.

Two days is sufficient for the Anglesey sites; add a day for St Winefride's Well and Tinkinswood. The island is compact and well-served by roads. Most sites require short walks across fields — bring sturdy footwear and be prepared for gates and stiles. If possible, visit Bryn Celli Ddu around the summer solstice to witness the alignment; otherwise, a torch will show you where the light falls.