Knowth

Knowth (Cnóbha in Irish) is a prehistoric tomb overlooking the River Boyne in County Meath, Ireland. It comprises a large passage tomb surrounded by 17 smaller tombs, built during the Neolithic around 3200 BC. It contains the largest assemblage of megalithic art in Europe and is part of the Brú na Bóinne World Heritage Site, which also includes Newgrange and Dowth.

The large mound is about 12 metres (40 ft) high and 67 metres (220 ft) in diameter, covering roughly a hectare. It contains two independent passages on an east–west line, leading to separate burial chambers, and is encircled by 127 kerbstones, of which three are missing and four badly damaged. The eastern passage reaches a cruciform chamber with three recesses and basin stones in which cremated remains were placed. The western passage ends in an undifferentiated chamber separated by a sill stone.

Knowth holds more than a third of the megalithic art of all Western Europe, with over 200 decorated stones found. Much is abstract and lies on the kerbstones near the passage entrances. Motifs include spirals, lozenges, serpentiform lines, crescent shapes and the oldest known illustration of the moon in history. Much of it was carved on the backs of stones, known as hidden art, which may mean it was meant to be hidden or that stones were simply recycled.

The east–west passages suggest an alignment with the equinoxes, which does not occur today, partly because later settlers destroyed or distorted the original entrances. After its initial use the mound fell into disuse, and a grooved ware timber circle near the eastern entrance was used for ritual, with votive offerings. Some 35 cist graves were found. In the late Iron Age and early Christian period it became a hill fort with ditches and souterrains, with ogham names carved, and became the capital of the Kingdom of Northern Brega.

The Normans used Knowth as a motte in the 12th century, and it later passed to the Cistercian monks of Mellifont Abbey as a grange. Most of the site was taken over by the state in 1939. The first thorough excavations began in 1962 under George Eogan of University College Dublin, who led work from the 1960s to 1980s, and parts were reconstructed. The site is 9 km west of Drogheda and open by guided tour only, from the Brú na Bóinne Visitor Centre in Donore.

The large mound has been estimated to date from c. 3200 BC. The mound is about 12 metres (40 ft) high and 67 metres (220 ft) in diameter, covering roughly a hectare. It contains two passages placed along an east–west line and is encircled by 127 kerbstones, of which three are missing, and four badly damaged. The passages are independent of each other, leading to separate burial chambers. The eastern passage arrives at a cruciform chamber, not unlike that found at Newgrange, which contains three recesses and basin stones into which the cremated remains of the dead were placed. The right-hand recess is larger and more elaborately decorated with megalithic art than the others, which is typical for Irish passage graves of this type. The western passage ends in an undifferentiated chamber, which is separated from the passage by a sill stone. The chamber seems to have also contained a basin stone which was later removed and is now located about two-thirds down the passageway.

Megalithic art

Knowth contains more than a third of the total number of examples of megalithic art in all of Western Europe; over 200 decorated stones were found during excavations. Much of the artwork is of an abstract style and is found on the kerbstones, particularly approaching the entrances to the passages.

Many of the motifs are typical: spirals, lozenges and serpentiform. However, the megalithic art at Knowth contains a wide variety of images, such as crescent shapes, and the oldest known illustration of the moon in history. Much of this artwork was carved on the backs of the stones; a type of megalithic art known as hidden art. This suggests all manner of theories as regards the function of megalithic art within the Neolithic community who built the monuments in the Boyne valley. It is possible that they intended the art to be hidden. It is also possible that they simply recycled the stones and reused the other side.

Astronomical alignments

The east–west orientation of the passages at Knowth suggests astronomical alignment with the equinoxes. The alignment at Knowth does not occur today. This is due to a number of factors. First of all, the passages were discovered by later settlers and were, to some extent, destroyed or incorporated into souterrains. In this way, the original entrances to the passages were distorted or destroyed, making it difficult to establish if an alignment ever existed. Further, excavations since 1962 under George Eogan resulted in the erection of a concrete slab wall inside the mound's west entrance, restricting any investigation into the possible alignments. It seems likely that the passages were intended to align. Also, the alignments of ancient monuments can change due to Milankovitch cycles. The most extensive research on alignments and astronomy at Knowth was carried out by American-Irish researcher Martin Brennan.