After researching, for some years, the historical significance of a mountain near Abergavenny I learned in March 2019 that it was on a possible route that the people took in transporting the first stones to Stonehenge from southwest Wales. Selecting the ‘walking’ button in Google maps from Preseli Hills to Gloucester illustrates this possibility. The mountain in question features the same rock type as that of the Altar Stone and so I decided to further my research.
For all that we currently understand of Stonehenge the Altar Stone is something of an ‘elephant in the room’, a stone of immense importance to the people who conveyed it to the henge and subsequently to many generations who went there to experience it, and yet it’s an enigma that seems largely overlooked by commentators. It is a central stone of unique rock type within the monument and was a focal point within the central area of Stonehenge in its completed phase. The red line in the photo in this link highlights the current position of the Altar Stone. This particular stone is undoubtedly and especially of huge importance in the understanding of the monument.
In general terms, the great stone monument at Stonehenge is constructed of three stone types, although there are numbers of sub-divisions of geologies. These comprise the largest stones, referred to as ‘sarsens’, probably from the Marlborough Downs around 20 miles away, much smaller ‘bluestones’ from the Preseli region in west Wales, and the Altar Stone, a unique stone type of all the visible stones within the henge being most likely composed of Senni formation Old Red Sandstone. Geological analysis of the Altar Stone is an extremely complex issue and the academic papers of Rob Ixer, Richard Bevins & Peter Turner, amongst others, are the most recently published expertise on the subject.
It’s not currently known exactly where the Altar Stone was sourced although general consensus among experts is that it most likely originates from the south Wales Old Red Sandstone geological outcrops- a huge area that spans from as far west as the Kidwelly region in Carmarthenshire and across the Brecon Beacons national park towards Hay on Wye and covers the Black Mountains. Discovering its provenance is like trying to find a needle in a haystack.
In its current state the Altar Stone is a sad prospect- a broken, obscured and half buried rock that’s covered by much larger fallen stones and might be described as resembling an unremarkable ancient pavement- if you can locate it at all. It isn’t visible to the vast majority of visitors to the site, as you need to be amongst the stones to see it. Full excavation of the stone has never been undertaken but it is believed to measure approximately 16 feet by 3.5 feet by 1.75 feet and to weigh six tons- by far the heaviest of the stones that were brought from the west.
Both the Altar Stone and the top of Ysgyryd Fawr, the Skirrid (or Great Skirrid), a mountain near Abergavenny, are composed of Senni formation Old Red Sandstone. The mountain marks the beginning (or end) of the western mountain landscape and the more gentle topography to the east.
New insights of academics and experts regarding possible route of transportation of the Preseli (west Wales) bluestones, by land, suggest that this mountain might well have been on their route to the henge.
Were these people in the Neolithic to have travelled via a ford of the river Severn near Gloucester then this mountain also happens to be very close to halfway on their route between the confirmed sources of the west Wales bluestones and Stonehenge.
It has previously been suggested that according to the theory of the bluestones being transported by river and coast, that the sandstone of Milford Haven may have been the source of the Altar Stone. This is now considered to be very unlikely. Mike Parker Pearson, director of the Stonehenge Riverside Project, among other experts now believe a land route to have been more likely. However, it is interesting to note that part of the coast and river route theory and the Milford Haven provenance was that it was the ‘exit port’ of the bluestones and therefore a likely source. [Atkinson (1979, 57 and 108)]
The two hills of Ysgyryd Fawr and Ysgyryd Fach (or little Skirrid, a hill 2 miles south of the great Skirrid) feature easternmost outcrops of Senni formation Old Red Sandstone and could arguably have been understood by the people who transported the bluestones to have formed a portal or gateway into and from the western mountain landscape. I believe that the Altar Stone of Stonehenge was sourced from either of these two hills, with the larger of the two (Ysgyryd Fawr) the most likely site.
That the mountain has an Iron Age hillfort on its spine was an early interest of mine but the fact that it’s a focus of numbers of myths and legends and that it had been known traditionally as The Holy Mountain of Wales is also worthy of note. The Holy Mountain. Wales is full of holy places- this is a bold and peculiar claim.
It’s a border spine of a place. It’s really not very practical for domestic interest. It’s a promontory. It’s a procession. It’s the last of the mountains witnessed on this possible route of the bluestones as they were on their way to the great henge. Its approximate north-south orientation means that it receives sunrise on one flank while the other sees the setting sun. It’s a high place of darkness and light. It’s a geographical watershed. It’s also split dramatically by a huge landslide, or series of landslides, which is likely pivotal to it being understood as a place of great significance. The name ‘Ysgyryd’ is thought to be derived from the word ‘ysgwr’, which in Welsh means ‘broken’- the great broken mountain- and around a thousand years ago, a chapel dedicated to Saint Michael, now all but gone, was built on the mountain’s summit.
Ysgyryd Fach (little Skirrid) is a fairly regular-looking hill. It seems to share none of the remarkable characteristics of its most unusual neighbour to the north with which it shares a name. The nominal association of Ysgyryd Fawr and Ysgyryd Fach may be due to the fact that both hills are of the same Old Red Sandstone formation on their summits- the rock-type that the Altar Stone is believed to be composed of.
In 2012 aerial photography of Ysgyryd Fach revealed a defended enclosure on the summit of the hill which may date from as early as the ‘Later Bronze Age or even Neolithic’.
The significance of this possibility is that were Ysgyryd Fawr a ceremonial or religious site then we may now also have present in the immediate local landscape a site that could have been domestic, a place perhaps used and lived in by the people who used the mountain, and maybe by those who were involved in the transportation of the bluestones to the henge.
I also believe Ysgyryd Fawr to be central to Stonehenge in another respect- that the relative geographical location of the mountain played a pivotal role in the siting and celebration of the great stone circle at that precise point on what we now call Salisbury Plain.
The Altar Stone’s present position is such that it meets the midsummer sunrise axis at an angle of 80°, along with the remaining upright stone of the Great Trilithon. However, due to the fact that this huge monolith, the tallest of the stones standing there today, was reset to its current position from a leaning position in 1901, its angle has generally been considered to be due to a mistake on the part of those who straightened the stone in the early 20th century.
In 2015, research by Tim Daw (a former English Heritage steward at Stonehenge) was published, in which he put forward the idea that the Great Trilithon, along with the Altar Stone and some bluestones in the same central vicinity were all placed by the Neolithic builders not at a 90° angle to the midsummer sunrise axis, but at an 80° angle- 80° being the difference between midsummer sunrise and midwinter sunrise in this region. According to Tim Daw’s research it is more likely to have been an intended design by the Neolithic people who built Stonehenge- and that the angle of the Great Trilithon today was, in fact, a careful and accurate restoration and not due to any mistake in the stone being restored to an upright position in 1901.
Ysgyryd Fawr and the Altar Stone are jointly aligned to the approximate horizon where the sun rose at Stonehenge at midwinter solstice 4,500 years ago. The Altar Stone currently lies, elongated, orientated to that horizon, which means that it is aligned towards midwinter sunrise at one end and towards its possible source, Ysgyryd Fawr, at the other.
The principal and most famous mythology of Ysgyryd Fawr is that its landslide chasm occurred at the moment that ‘the veil of the temple of Jerusalem was rent in twain’, the moment of the Crucifixion of Jesus Christ and His ascension. This in itself is interesting. One of very few things that I feel quite certain about regarding the mountain’s history is that it did not split at that time. The general understanding is that the mountain split at some time during the last Ice Age, although it has not been scientifically established.
But what this might inform us of is that this place needed to be claimed as holy for themselves by the people of this much newer faith. It needed a really big moment of Christian significance to claim it as holy for themselves and their church, and they didn’t hold back in making a big claim in the case of this mountain- nothing less than the moment of the Crucifixion.
And as is the case with many high places of earlier sanctity and religious focus, Saint Michael the Archangel is the entity who inevitably and successfully performs the task. Saint Michael, the mythology informs us, successfully resists the temptation of the Devil with the help of the forces of God right here on this mountain.
From a Christian perspective, the mythology is true- the forces of the Devil and the forces of God really were in combat on this mountaintop while Saint Michael the Archangel was present. True, not in a supernatural sense, but because the Christians in this part of Britain chose this scenario symbolically in their need to bury the people’s strong remembrances of the celebrated sacredness of this site in a much earlier period- necessarily, in their understanding, a religion of the Devil.
In another myth, the Devil himself makes an appearance on Ysgyryd Fawr. The dramatic chasm in the mountain is also known in folklore as the Devil’s heel print and within that chasm is an eye-catching lectern-shaped rock poised above the ravine known as the Devil’s Table.
These rich mythologies seem to me to hold some residual ancient truths that have been woven, twisted, and in time, confused. However, these peculiar tales are remembered for a reason.
A tradition which held in the region (and more broadly across Wales) into the last century was that the topsoil of Ysgyryd Fawr was holy and particularly desirable and fertile. As a result it was sourced by people to be sprinkled on coffins at funerals, used by farmers to make their fields more productive and it is said that it was used in the foundations of some churches.
I believe that Ysgyryd Fawr was considered a ‘cathedral’ of a mountain long before the construction of the chapel on the summit/Iron Age hillfort on the mountain’s spine. At the time the Altar Stone was quarried I suspect that it was one of the most revered sacred sites in this region of Britain.
There was an archaeological discovery made in the late 1960’s about a mile from Stonehenge and on a ridge above it. Two chalk plaques were uncovered from the earth which feature mesmerising and quite beautiful artwork.
Of course, to us now the artwork ultimately is anything any individual chooses to see it as but I think that the artwork on the larger of the two Stonehenge chalk plaques, as they came to be known, represents Ysgyryd Fawr. I refer to the roughly M-shaped figure at the top left of the larger plaque which can be viewed here.
The central element of the artwork suggests a representation of a Trilithon.
The archaeological dating of the chalk plaques differs somewhat in presentations from English Heritage. It may have been created and deposited around 4,000 years ago or alternatively from the period 4,920 years ago to 4,600 years ago. If it were from the first of these dates then Stonehenge was in its completed phase of construction with every stone still present on the site in place. However if it was from the broader and earlier date range then it brings up a tantalising possibility- that this image made in chalk all those millennia ago, was created to depict a bluestone Trilithon which likely existed originally standing at the site or in the far west of Wales prior to the moving of the all the bluestones to the monument.
This artwork in chalk created by the hands of an artist, or artists, in ancient times may come to be understood as the earliest known depiction of a recognisable mountain currently known to humanity.
In their paper ‘A detailed re-examination of the petrography of the Altar Stone…’ Ixer & Turner write “a lithologically unremarkable, grey-green, micaceous sandstone is perhaps the most famous Welsh lithic export in the world”.
It has surprised me during the period of my research on the Altar Stone just how few of us are aware even of its existence, let alone its central importance, within this world-famous monument.
I hope that this article will at least make some more people aware of the Altar Stone and that we might discover its provenance, perhaps beyond reasonable doubt if not with 100% certainty, in the months and years to come.
Geological analysis of rock samples from Ysgyryd Fawr will be published on this website soon.