The huge cruciform east chamber at Knowth is the largest megalithic chamber in Ireland, with its capstone
placed some seven meters above the floor, crowning a complex corbelled ceiling.
From the entrance kerbstone to the inner endstone, the monument measures
forty meters, making it the longest neolithic passage in Europe. It is twice the length of the passage at Newgrange. The orthostats (passage stones) and roofslabs are
decorated with a variety of angular and curve-linear motifs, many of which echo the patterns on the east Entrance stone.
The Entrance Area
During excavations at Knowth it was discovered that the first five meters
of the passage had been destroyed by a defensive ditch excavated inside the kerb during the seventh and eighth centuries. The Entrance, in a most bizarre effort to make the monument tourist-friendly, was sealed off by a slab of concrete. Visitors enter the interior of the mound by crossing a metal bridge and through a door to the left, behind the Entrance stone. The fully-engraved Entrance stone has a well-defined vertical groove, similar to West Entrance stone, and Entrance stone and Kerbstone 52 at Newgrange.
There are a number of interesting features around the entrance to Knowth East. A small limestone pillar stone, about one meter high, was found in the largest of seven settings, directly in fromt of the entrance. The pillar was fallen and the excavators though it may have been deliberately knocked. The standing stone has been re-erected at the centre of the largest setting, which is an oval, saucer-shaped depression four by three meters in diameter. Another much smaller setting is directly outside the entrance. The other settings are U-shaped, three to the north and two to the south of the entrance.
There are many egg shaped 'exotic' stones, and granite cobbles spread on the ground in this area, and lots of chunks of white quartz spread out before the entrance. The granite cobbles were transported from the Cooley peninsula 90 kilometers to the north, while the closest source for the quartz is the Wicklow mountains 60 kilometers to the south. The stones were surely transported to the Boyne Valley by boat.
The Entrance stone, K11, is divided into two panels, seperated by a central picked line. The right-hand side has a bold design of rounded rectangular nested arcs rippling out from a circular motif at the centre, the left-hand side has a simpler version of the same pattern. The design, quite different in style to anything at Newgrange, has a great sense of movement, perhaps representing the rapidly shifting light near the equinoxes. The artwork at Knowth has a uniform style of its own, and the East and West Entrance stones, and the so-called Guardian stone in the west passage all share the same sensibility and may well have been carved by the same artist.
The east passage at Knowth is an amazing neolithic structure, the longest passage-grave in Europe. When the entrance was discovered during the excavations in 1968, George Eogan became the first person to enter the passage and chamber since medieval times:
I moved along the passage, which was a metre wide and slightly more in height. After a couple of metres, obstructions arose, due to a downward sloping capstone and inward leaning orthostats. Having got past these, we came to a well-preserved stretch, but soon had to go on hands and knees again along the stone-littered floor. Farther on we could again stand upright. In this area was a cracked capstone highly decorated with chevrons, and in addition orthostats on both sides now had megalithic art. But this was only the beginning of many stunning features that still awaited us.
Many of the passage orthostats had leaned inwards under pressure from the massive weight of the cairn. The excavators dug a long trench and removed the roof corbels to straighten the passage stones, in a similar fashion Newgrange.
The long passage leads straight into the heart of the massive cairn, with some wonderful carvings on the walls and roof. About two thirds of the way along the passage is another entry feature which seems to be the entrance to an earlier phase of the monument. There is a cluster of decorated stones on both sides of the passage at this point, and a roofstone is elaborately carved with a panel of zig-zag motifs. This position marks a very definite boundary within the passage.
From this point, the excavators were unable to straighten the passage stones; as Michael O'Kelly found at Newgrange, the roof of the passage rises and becomes part of the corbelled chamber roof. The last six meters of the passage involves crawling through a narrow gap where the orthostats have leaned in, not for the claustrophobic!
For this reason there is no public access to the east chamber. To fix this and straighten the passage stones would have involved dismanteling the corbelling, which was rightly thought to be a bad idea. George Eogan describes his first view of the chamber in 1968:
We continued our exploration, rather impatiently because of more hindrance caused by inward leaning orthostats. These touched each other at the top, and a void above had dry-stone walling above them. I now thought that the passage consisted of a two-tier structure, and in my excitement and probably not considering the dangers, I climbed up to the 'upper' passage. In fact I was now walking along and over a spread of cairn derived stones. This upper 'floor' was above the tops of the orthostats and it sloped gradually upwards.
It suddenly came to an abrupt halt, and I felt as if I were suspended in mid-air!. But still not suspecting what might exist before me, I flashed my lamp around. And there was an astonishing sight: a great space with corbelled sides narrowed beehive fashion to a single closing slab at the top.
That was only part of the structure. When I flashed the light downward, what I saw was even more remarkable, a great chamber with a rounded ground plan.
The East Chamber
I descended into the chamber, how I did so I cannot think, but I must have jumped two metres or more from the top of the orthostats. The chamber provided further excitements. Two side recesses and an end recess opened off it, making it cruciform in plan, and the orthostats as well as some of the overlying corbels were elaborately decorated. One of the side recesses had a portal-like arrangement consisting of two tall jambs again with decoration.
The huge cruciform East chamber of Knowth measures
about eight meters across from north to south, and is even more massive than the chamber in Newgrange. Each of the three recesses contains a basin stone. Large stone slabs, which are rudimentary basins are found in the left and rear recesses. The basin in the rear or end recess has a number of small circular engravings and a faint pecked inner boundary line around the rim.
The massive corbelled roof had settled over the milennia and rotated, pushing many of the orthostats out of alignment, and oaken timber props were added to support the chamber and recesses. The roof is composed of ten courses of corbels, each overlapping the course below. The lower courses are built with massive slabs, some almost two meters long. The corbels decrease in size as the roof gets higher, closing up the space until the top is reached.
The chamber is closed by a capstone slightly more than six meters above the floor of the chamber. Smaller spall stones were wedged under the corbels to keep them at a slant, allowing rainwater to run off the outer surface, keeping the interior dry. A quantity of small stones found on the chamber floor are displaced spalls which probably fell out when the chamber settled in antiquity.
The Dagda's Cauldron
I entered the recess. There was more art, but something even more exciting: a large stone basin over a metre in diameter, ornamented on the outside with parallel horizontal scoring and on the inside with arcs and rays.
A large stone basin is located in the right hand recess before a beautifuly decorated stone. The basin is crafted from a huge lump of granite and measures 1.2 m in diameter. One of the first things to note about this massive and wonderful rock is that it was placed here before the chamber was built - it is much too large to have been brought in later.
The basin is shaped like a cauldron - an important motif in Irish mythology. The
most famous cauldron belonged to the Dagda, a chieftan of the Tuatha De
Dannan who lived in nearby Newgrange. His cauldron was one of the four
chief treasures that the De Dannans brought to Ireland with them, the
others being the Stone of Destiny at Tara, the Sword of Light and Spear
of Lugh. The cauldron was a vessel of plenty - no one ever left it hungry,
and it never ran out of food. It also had the power to regenerate life: dead bodies
could be placed into the cauldron and drawn out alive and whole again.
The symbolism gives us some insight into neolithic religious beliefs,
as archaeologists believe the basins were used to contain cremated ashes.
It is highly probable that these chambers were viewed as wombs, and that
rebirth and reincarnation beliefs were a fundamental part of the rituals
that went on here.
The centre is dished and engraved with a rayed solar design - a central
circle opens into 12 radials arranged six on either side of a central axis.
At the top, another circle becomes a nest of arcs. The image above is
taken from Martin Brennan's book The Stones of Time, and I have added the circle in the centre which
it represents the meeting of the sun and moon at Knowth, when once or
twice in each cycle, both passages were illuminated at the same
time on specific dates. The outside is decorated with a series of seven
grooves which run around the basin which give way to a solar/lunar emblem
at the front. The grooves are interupted by four vertical grooves on the right side ov the bowl. The back stone of this recess also has some interesting
engravings: diamonds, lozanges, cupped arcs and some stars.
A fine artifact was discovered in the entrance to the northern recess, close to the basin.
It is a decorated mace head, carved from an incredibly hard piece of flint,
and probably ceremonial.The flint is thought to originate from the Orkney Islands. It is engraved with whorls and spirals in a similar fashion to the Entrance
Stone at Newgrange,
and is a precurser to Celtic art.
Three of the artifacts found at Knowth, the granite basin, flint macehead and the long grooved object from the west pasage are the works of master craftsmen. The macehead and grooved object are on display in the National Museum in Dublin.
The Secrets of Knowth, a short clip from RTE news about the Knowth laser scanning project, from May 2012.
Canadian scientist Philip Stookie, has suggested that the engraved slab at the rear of the east chamber bears
an engraving which may be the earliest map of the surface of the moon.
This idea supports the work of several researchers who believe that illumination
of chambers by the moon was of as much importance as the sun, and that
certain full moons near the equinoxes could possibly have shone on this
However, due to the damage to the entrance during the Iron age, it's being blocked up with a
concrete slab during the restoration, and the fact that Knowth House blocks the eastern horizon, we can only speculate about possible alignments, or attempt simuliatons with a computer.