Banner: sunset over Knocknarea.
Sunrise on October 29th, 2019, viewed from Listoghil, the central monument at Carrowmore.

Who were the builders of the Monuments?

Ireland's first megalithic monuments were built by early farmers, tribes of neolithic cattle herders who made an epic journey from Brittany in France around 4,100 BC, to sail up the west coast of Ireland settle on the Cúil Iorra peninsula in Sligo.

For many years—since the start of antiquarian interest in ancient times in fact—there has been continuous debate and speculation about the movements of ancient people. This very question was a hot topic in Ireland in the 1870's and 1890's and again in the 1940's and 1950's to support various nationalist and cultural agendas.

However, with the advent of aDNA ( the 'a' stands for ancient ), many of the mysteries of our ancient origins are being unravelled. It all began in 2015 when geneticists from Trinity College in Dublin, working with a team of archaeologists in Belfast, sequenced DNA from the bones of a neolithic woman who's remains had been excavated in 1865.

What the Ballynahatty woman may have looked like.
What the Ballynahatty woman may have looked like. Reconstruction by Elizabeth Black.

We now know that the farmers who build passage-graves such as those found at Carrowmore, Carrowkeel, Loughcrew and in the Boyne Valley are descended from the first agriculturalists who domesticate cerials and tame cattle in Anatolia, Turkey, some 10,000 - 12,000 years ago. The first megaliths are also found in this region.

Our farmers migrate through the Mediterranean with their herds of cattle and fleets of ships. They pass through Sardinia, where their closest modern genetic relatives still live; they colonise the Iberian peninsula, and up along the Atlantic facade to Brittany, where the megalithic passage-grave culture takes root.


The oldest monument discovered so far in County Sligo is the remains of a causewayed enclosure at Magheraboy, just outside Sligo. This structure has been dated to about 4,150 BC using a piece of an oak plank that was found in site. Causewayed enclosures are a special type of neolithic structure, with segments of ditch running around the outside of the monument, interrupted by causeways. A timber pallisaded fence was built within the ditch, which indicates that this is not a defensive structure.

The Causewayed Enclosure at Magheraboy in County Sligo
The Causewayed Enclosure at Magheraboy in County Sligo.

Magheraboy is the second causewayed enclosure to be found in Ireland. The Sligo causewayed enclosure at Magheraboy is currently the oldest dated example in either Ireland or England, and gives us an approximate date for the arrival of farming with the passage-grave people: about 4,150 BC.

At Carrowmore in County Sligo, during excavations by Dr. Burenhult and his team during the late 1980's and 1990's, pieces of charcoal were used to secure some extremely early dates, suggesting that the circles were built as far back as 5,400 BC. However, these dates were considered to be far too early by many archaeologists, being contemporary with the beginnings of megalithic construction on the continent.

The Kissing Stone or Leaba na Fian at Carrowmore in County Sligo, copy of an illustration by Gabriel Beranger.
The Kissing Stone or Leaba na Fian at Carrowmore in County Sligo,
copy of an illustration painted by Gabriel Beranger June 23rd, 1779.

Current research suggests that Carrowmore is indeed the oldest collection of megalithic monuments in Ireland. In 2013 Stefan Bergh and Robert Hensey re-dated the Carrowmore monuments using C14 dates taken from pieces of red deer antler which had been included with the neolithic cremations. The secure range of dates demonstrates that the Carrowmore dolmens were in use from 3,800 to 3,000 BC.

Dolmen 52 at Carrowmore.
An image of Carrowmore 52 by William Alfred Green from around 1910.

The cairns at Carrowkeel are an inland extension of the Carrowmore complex and seem to date from about 3,500 BC onwards. Interesting new research is taking place on the human remains from Carrowkeel, which were recently re-discovered in Cambridge University.

The passage-graves at Loughcrew have no dates from modern excavations, and it is assumed that the monuments are around the same age as, or slightly younger than the Carrowkeel cairns, dating from between 3,500 to 3,000 BC. There appear to be no surviving uncremated neolithic bones from Conwell's excavations at Loughcrew; the best chance of dating the monuments would be to date some of the red deer antler, as Bergh and Hensey did at Carrowmore.


The earliest Irish megaliths are built with large blocks of stone raised above the ground on a circular platform. The platform or tertre was surrounded by a ring of stones, with a passage connecting the circle to the chamber.

The circles at Carrowmore are built from local glacial erratic blocks of gneiss. In many cases the boulders were split in half to provide better building materials. There are few examples of limestone being used at Carrowmore, the best example being the massive capstone on the dolmen of Carrowmore 51, Listoghil. This massive slab of limestone was quarried in the Glen, close to Primrose Grange on the south side of Knocknarea.. These simpler monuments have tiny chambers, just large enough to place the cremated human remains.

At Knocknarea and Carrowkeel, monuments somewhat later than the Carrowmore circles are constructed from slabs of limestone which were quarried close by. While the inner features of Queen Maeve's cairn remain hidden, Carrowkeel has some superb examples of limestone chamber construction. The cairns which cover these massive constructions are generally built from quarried limestone, with some glacial erratics included. At the central dolmen at Carrowmore and in in some of the Carrowkeel chambers, blocks of sandstone were used at construction points which carried most weight.

Excavation of Site K beside Newgrange in 1966.
Excavation of the carefully constructed multi-phase Site K beside Newgrange in 1966.

The Boyne Valley builders took great care in the construction of their mounds. The chambers and kerbs are some of the largest constructed in neolithic Europe.

When the passage and chamber of Newgrange were covered over, the builders carved grooves on the upper surfaces of the stones to channel off water and keep the interior dry. Several of the slabs used in roofing were engraved before being set in place, most notably the marvellous ceiling of the right hand recess at Newgrange. The chamber is corbelled, which means that each layer of stones added by the roofing gang overlapped the last by several inches. The corbels were tilted, like our slate roofs, again to allow the water to run off, and they were packed with small stones known as spalls.

The building of the actual cairn was the last part of the process. The chamber of Newgrange was covered in a small cairn which reached to the capstone. This would have greatly stabilised the structure. Then the cairn proper was built - again a complex affair. Turves were stripped from the surrounding area and the cairn material was carefully built up in alternate layers of stone, rubble and organic material.

Why were they built?

The number three and the cross-shape were important symbols to the cairn builders. The symbolic importance of the trinity can be traced back to the origins of Irish megalithic culture at Carrowmore in Co. Sligo. The central chamber of Listoghil, which is oriented to the south east is at the centre of a trinity of sites which includes Knocknarea and Carns Hill. In addition there are three arcs engraved on the roof-slab of Listoghil. There are several early monuments in the region with the classic cruciform chamber plan - Barnarashy 63, Knocknarea 1 and Carrowmore 27.

At Carrowkeel the triune of sites is more difficult to spot with the layout of the monuments, but could be Kesh Corran , Treanmacmurtagh Cairn and either Cairn F or K. However there are several monuments with cruciform chambers - Cairns C, E, F (double cruciform), G, K and M. Sheemor in Leitrim has three cairns sitting on its flat summit, the central mound capped by a modern Christian cross which is lit by floodlights at night. Loughcrew has three distinct peaks and many cruciform chambers. And at the Boyne Valley, the triple spiral as mentioned above is the key signature.

Cairn V at Loughcrew.
Cairn V looking south-east, the general direction of the Boyne Valley, on a hazy afternoon, Easter 2011. Loughcrew commands wide views, and the Hill of Tara and the Wicklow Mountains are visible in clear weather.

Neolithic Symbolism

The use of the cross as a symbol needs to be examined in relation to Irish sites. Not many academic researchers have ever taken this subject on and given it the thorough investigation it deserves. The cruciform plan was in use from the earliest building phases on the west coast of Ireland. I believe the real purpose of these buildings can be understood by examining their symbolic attributes. As shown above, the symbol of the cross is as old as this type of monument, as is the repetition of the number three and the alignment or orientation to the movement to a heavenly aspect. In addition Cairn G at Carrowkeel and Newgrange have stone covering slabs still in situ, though many other mounds must have had them.

In a situation such as Newgrange, we are faced with a parallel set of symbols as the resurrection scenes in the gospels. An initiate is placed within a stone tomb for three days, which in this case correspond to the winter solstice festival of rebirth and the supposed birth date of Jesus, The interior of the tomb is laid out in the shape of a cross - as are modern churches and cathedrals. On the third day the stone door is moved aside and the initiate, newly reborn in the sun, emerges into the light. The symbolism of the sunbeam within the chamber is very potent - penetrating light illuminating the mind of the initiate.

A further confirmation of this practice is engraved on the Entrance stone at Newgrange and beautifully illustrated in the Books of Kells and Durrow. The Chi Rho symbol which represents the birth of Christ is engraved within the Triple Spiral, where the top two loops meet at the centre.


Megalithic monuments are found throughout Ireland. Reports written over the last two hundred years show that probably as many have been destroyed as remain. These monuments are found in most Irish counties, though many are in poor states of repair and many have no obvious chamber. A large number have totally disappeared because their stones were robbed for convenient building materials.

Ireland has several large complexes where large numbers of cairns are clustered together - Carrowmore, Carrowkeel, Loughcrew, the Boyne Valley, at Lough Corrib and in the Wicklow Mountains. There are also many other individual sites spread out on mountain tops, the greater portion across the northern half of the island.

In general passage-graves are found in commanding locations which usually have superb views of the surrounding horizon and are often positioned in view of other cairns. However, several of the largest Irish sites are located in lowland locations - Carrowmore; Heapstown; Ballymacgibbon and Echoy's Cairns at Cong and Ballinrobe; and the mega cairns in the Boyne Valley. Water often plays an important part in their location - the Boyne at Newgrange and the Uinshin at Heapstown, while Knocknarea is surrounded by sea on three sides. Alignments are often found with prominent mountains or hills, which are often the location of another site.

Painting by Jim Fitzpatrick.

Mythology of the mounds

Ireland's ancient manuscripts record the names of several tribes who were said to have invaded the island in the mythological past. In order of arrival, the Formorians, the Parthalonians, the Nemedians, the Firbolg, the Túatha Dé Danann and lastly the Celts or Milesians are the tribes said to have settled here. Ireland was considered a magical homeland by the tribes who came here. The best known group were the Túatha Dé Danann, The Tribe of the Goddess Danu. They are said to have arrived from the North and West in flying ships, bearing four great treasures - The Sword of Núada; The Dagda's Cauldron; The Stone of Destiny; and The Spear of Lugh. They landed at Lough Corrib in Co. Galway and on the mountain of Sliabh an Iarann in Co. Leitrim.

The First Battle of Maigh Tuireadh, which took place on the plain of Cong by the north shores of Lough Corrib, was fought between the Firbolg and the Túatha Dé Danann.Two large monuments, Ballymacgibbon Cairn and Eochy's Cairn, remain here and several others are said to have been destroyed. Connaught's four stone circles are to be found here, as well as several cashels, ringforts, caves, standing stones, and a strange modern stepped pyramid and inscribed stone known as The Gods of Neale.

The Second Battle of Moytura took place on the hill above the eastern shore of Lough Arrow, near the Bricklieve Mountains. The Second Battle was fought between the Túatha Dé Danann and the Formorans, and was a complex affair which deserves a lengthy page of its own. Lugh of the Long Arm led the Túatha Dé Dannan to victory over their opponents and oppressors, and killed his grandfather Balor of the Evil Eye who was in charge of the Formorian army.

The place where he put out Balor's Eye is today marked by the eerie lake of Lough na Suil, The Lake of the Eye (see top picture). Balor's destructive Eye burned a great hole in the ground and disappeared, and a lake was formed on the spot. In a regular cycle, the length of which I am not sure, the water vanishes for a few days leaving a crater with a large, deep hole at the bottom.

Stone basin from Knowth.
Stone basin from Knowth. The Dagda's Cauldron? One of the four treasures brought to Ireland by the Túatha Dé Danann.

In general they are associated with many ancient sites, and the Dagda in particular was known as a builder of monuments. He resided at Newgrange for a long time until his son Aongus won the mound from him. 

Circle number 7 at Carrowmore in County Sligo .
Circle number 7 at Carrowmore in County Sligo.

Megalithic art

One of the best known aspects of the passage cairns are their art, an un-interperetated symbolic language that and ornamentation. These engravings are the earliest writings in Ireland and among the oldest in Europe. They are documents in stone written in a symbolic language which seems to incorporate the light and motion of the heavens.

The stone basin.
The Dagda's Cauldron, the Great Basin of Knowth, right recess, east chamber. This beautiful chunk of granite was carved in position; it is much too large to have been moved in after the chamber was built. Picture © Padraig Conway

That these engravings deal with astronomical themes is demonstrated in several sites, where the artwork is illuminated by the light of the sun or moon at a chosen time in the cycle of the body in question. This is demonstrated at Cairn G , Carrowkeel (no artwork), Cairns L and T, Loughcrew and Boyne Valley sites in these pages. Knowth alone has 50% of the engraved stones in Ireland. Early engravings have been discovered in recent years on the chamber of Listohil monument at Carrowmore in Co Sligo. Heapstown Cairn, also in Sligo is known to have had several engraved stones, with perhaps an ogham stone standing at the top of the mound. Only one stone remains visible today, as many were robbed from the site in the last century.

Carrowkeel pottery and stone basins

There are several types of artifacts which are associated with chambered cairns. Of the few items that are found in these monuments which can be said to date to the builders, the most common are fragments of ancient pottery. On a few occasions complete pots were recovered, and since these were first found in the Bricklieves, these are known as Carrowkeel Ware. The example illustrated above is the Barnarashy Vessel from near Carrowmore, and is found on the old Irish 4p and 5p stamps. The vessels were made from coarse, gritty clay sometimes mixed with broken shells and always decorated with grooved and pitted designs which complement the engraved artwork of the cairns.

Neolithic pottery.

This Carrowkeel Ware is associated with cremation and burial as great quantities of ashes are found buried under the passages, chambers and recesses of these monuments. In Celtic folklore and mythology cairns were sometimes raised over the bodies of slain warriors, but never mention cremation, which is obviously a very early form of burial. The cairns are called passage-tombs because so many cremated remains were found within them whenever they have been opened.

The location of the destroyed burial cairn of Eochaidh, King of the Firbolg, at Ballisodare in County Sligo.
The location of the destroyed burial cairn of Eochaidh, King of the Firbolg, at Ballisodare in County Sligo.

However given detailed study it is clear that these monuments were in fact the oldest sacred buildings in Europe, and were probably used much as modern temples are today. Rituals such as birth ceremonies; communions; marriages; ordinations; prayer, meditation and contemplation; initiations and finally death would have taken place within the chamber. The Carrowkeel pots may have been funerary urns or prehistoric chalices. The Essenes of Quamram had a ritual of passing the cup which was adopted by the early Christian Church; it is quite likely that this was descended, as so many other Christian symbols are, from prehistoric Ireland.

Neolithic pottery.

As the culture developed the cairns got bigger in size. At Carrowkeel stone trays were described in the recesses of Cairns G and K. Several stone basins were found at Loughcrew, including the large example in Cairn L. The Boyne Valley chambers all have large basins, one smashed in Dowth South, four in Newgrange and two at the main site of Knowth, the finest of them all being the beautiful engraved basin in the Eastern chamber illustrated here. The whole massive cairn was constructed around this basin, which may well be the Dagda's Cauldron, one of the four treasures brought to Ireland by the Túatha Dé Danann. This spot was an important setting out position for many of the monuments in the Boyne Valley, as 10 minutes experimenting with a drawing compass and plan of the monuments will prove.


Almost all of the Irish passage-graves have traces of quartz in some form or other, and many individual monuments had names such as Fin Cairn and Carn Bán, both of which mean White Cairn. Quartz was widely regarded as a sacred stone by ancient cultures all around the world and is a key component in our modern technological devices today.

Quartz was known as Grian Cloch, meaning Sun Stone to the ancient Irish. The traditions which still survive in Ireland today of covering graves with quartz chippings go back to the stone age. In the neolithic, use of quartz was imported from Brittany, where splintered quartz is often found in passage-graves, possibly a tradition adopted from Breton mesolithic hunter-gatherers. We see this custom being continued when farming arrives in County Sligo.

During the excavation of the causewayed enclosure at Magheraboy, a broken axe-head was placed in the ditch, surrounded by a ring of thirty-five fragments of poined quartz, almost like a model of an early passage-grave. Macalister found many fragments of splintered quartz in the chamber of Cairn F in Carrowkeel, while Cairn K had visible chunks of quartz until recent years.

While pendants are commonly found in these monuments, it is rare to find examples made from quartz. Two examples are known, one from the chamber of Circle 4 at Carrowmore, the other from Cairn R1 at Loughcrew. The best-known use of quartz in neolithic Ireland is the contraversial quartz facade erected at Newgrange.

Quartz at Knowth.
Quartz, sourced in County Wicklow during the neolithic, uncovered by excavation at Knowth.

Other items recovered in chambered cairns are chalk and stone spheres, stone pendants and bone or antler pins. There are examples of the spheres from several sites on display in the National Museum, including two mysterious artifacts found under the basin in Cairn L, Loughcrew. The chalk balls are smaller and were probably used to teach positions of the sun and moon on the horizon when held out at arms length during an astronomical ritual. I think this idea makes sense as several chalk balls were found in the chamber of Cairn G at Carrowkeel, where the roofbox demonstrates great interest in the movements of the moon along the horizon from major to minor standstill. This concept can also introduce a unit of measurement as the sun and moon both measure 0.5 degrees as they rise and set.

Bone and antler pins from Loughcrew and Carrpwmore.
Bone and antler pins from Loughcrew and Carrpwmore.

Pendants are considered to have been hung around the neck, and Michael Herity's Irish Passage Graves has a photograph of a model wearing a selection of pendants from the Mound of the Hostages at Tara. Another suggestion is that the pendants were used as pendulums for dowsing, much as they are in modern healing. In a few cases larger pendants which look more like ritual axe heads have been found. The outstanding example of a small carved stone is the Knowth Macehead which was found buried beside the basin in the right recess of the East chamber. This beautiful artifact is made from extremely hard flint and is engraved with swirls and spirals which rival the Newgrange Entrance Stone in their excellence.

Carved antler pins, sometimes with mushroom-shaped heads are found, with a particularly fine engraved example coming from Fourknocks. These may have been used as clothing fasteners, or as a drawing stylus for ground diagrams and Carrowkeel Ware decoration. Many of the finds discussed here were found among the cremations and bear burn marks from the fires.

  massive henge near Dowth.
The massive henge near Dowth. This enormous circular monument has no defensive features and was a gathering place for huge crowds of people.