The term "henge" was first applied to monuments such as those covered in this description by T D Kendrick when reviewing archaeological work between the Wars (Kendrick & Hawkes 1932, ch. VII). General accounts of the class accompanied reports of excavations of henge monuments at Arminghall, Norfolk (Clark 1936), and Dorchester, Oxfordshire (Atkinson et al 1951), and also as a result of work at the Priddy Circles, Somerset (Tratman 1967) which cannot now be regarded as henges at all. General accounts include those by Wainwright (1969), Burl (1969), Catherall (1971), and Clare (1986). The most recent synthesis and check-list of the class is that published by Harding and Lee (1987). In addition to the reports already mentioned, key excavations include those at Woodhenge, Wiltshire (Cunnington 1929), Thornborough, North Yorkshire (Thomas 1955) Avebury, Wiltshire (Smith 1965), Maumbury Rings, Dorset (Bradley 1975), Gorsey Bigbury, Somerset (ApSimon et al 1976), Condicote, Gloucestershire (Saville 1983), and Maxey, Cambridgeshire (Pryor & French 1985).
The most distinctive components of any henge monuments are its bank and ditch. Henges can sometimes be recognized by the remains of the ditch alone because these are generally fairly substantial features. Overall dimensions vary greatly, but no henge ditch is less than 2.5m across and many are over 8m wide; Coneybury is 5m, Woodhenge 9m-12m, and Avebury 21m. Cross-section profiles range from V-shaped through to U-shaped, sometimes even within the same monument. The depth of the ditches varies from less than 1m at Maxey to over 7m at Avebury; henge ditches are typically between 2m and 3.5m deep.
In their construction, henge ditches share many features. Most seem to have been excavated in sections rather than as a continuous length, but the sections are generally well joined together and can only be detected from the profile of the ditch floor and the angled rather than flowing shape of the ditch in plan. Treatment of the terminals includes simple rounded ends, squared terminals as at Hutton Moor, North Yorkshire, and Coneybury, Wiltshire, and expanded terminals as at Fobbing, Essex, and Westwell, Oxfordshire.
At Maumbury Rings, Dorset, a series of circular shafts some 0.9m in diameter and up to 6.5m deep had been dug at intervals in the bottom of the ditch. Assuming an even spacing of them all around the henge there may originally have been as many as 45. Similar, although rather more modest pits in the floor of the ditch have been recorded at Arbor Low, and possibly Avebury.
Most henges have either a single ditch or a pair of concentric ditches in either case forming a roughly circular or oval enclosure. There are, however, exceptions. Mayborough, Cumbria, seems to lack a ditch entirely, while Newton Kyme, North Yorkshire, appears to have three concentric ditches. It is not known whether all the ditches at multi-ditched henges are of the same date or not.
The soil and bedrock derived from the ditch was used to build the henge bank which lay either outside the ditch in the case of henges with one circuit of ditches or between the ditches in the case of henges with a pair of concentric ditches. The sizes of the banks varied proportionally with the size of the ditches. Typically, however, they seem to have been fairly broad at the base, 5m - 30m wide, and surviving up to 5.5m high in the case of Avebury.
In construction, the banks of henges comprise piles of turf and topsoil at the core with layers of redeposited bedrock above. No certain evidence for internal revetments or constructional features has been found, although at Avebury and some other sites traces of an external stone and/or timber revetment have been found suggesting that in at least a few case the lower parts of the banks had vertical faces.
Little is known about the surface of the banks when first constructed, although at Thornborough, North Yorkshire, the bank of the central circle seems to have been artificially coated with a layer of gypsum to whiten it (Thomas 1955, 429).
One exception to the normal tradition of henge construction is at Mayborough where pebbles and small stones seem to have been used in the construction of the bank.
In some henges the bank and ditch are separated by a berm which may be up to 6m wide, as at Maumbury Rings.
Together, the bank, ditch(es), and any intervening berm occupy a significant proportion of the ground area of the monument, but arguably the most important part of the site is the interior. These tend to be flat and fairly level, circular or oval in plan, their outline being determined by the plan of the surronding ditch. As a general rule the diameter of the central area is about 75% of the external diameter of the ditch, but there are exceptions to this. In overall size, henges range from small examples such as Milfield South with an external diameter of perhaps 40m up to the largest known henge at Avebury with an external diamter of over 427m.
Access to the central area appears to have been by way of formal entranceways through the earthwork. Most sites have either one entrance or two opposed entrances, although at Avebury there were probably four entrances. In general, the henges with two entrances are larger than those with only one although there is considerable overlap in the range of sizes represented. The largest henge in England, Avebury, has the most entrances.
The alignment of henges seen in the position of their entrances is highly variable and may have been as much conditioned by local topography as by any preferred orientation. There is a slight tendency for henges with a single entrance to have that entrance set in the north or north-east sector while sites with two entrances to have axes aligned SE-SSE to NW-NNW or ENE-E to WSW-W.
At henges with two opposed entranceways the plan of the ditches is often slightly asymmetrical and the width of the entrances different. For these reasons the main axis of the henge, as defined as the line through the middle of each entrance, only rarely passes through the true centre of the site.
At some henges the central area is virtually devoid of evidence for activity or structures, as for example at Big Rings, Dorchester, Oxfordshire. To what extent this is a real pattern or the product of subsequent damage and/or unlucky investigations is not at present clear. The majority of henges do contain internal features of various sorts, principally: portal settings, timber circles, post rings, four-stone settings, stone circles, monoliths, standing posts, pits, coves, post alignments, stone alignments, burials, central mounds, and stakeholes. To what extent any or all of these components should be seen as primary features is not clear. It may be noted, however, that many exist elsewhere as single monuments in their own right which raises the possibility that some at least were added to henges at a later date, perhaps because of the continuing significance of the site.
Portal settings are currently known at eight sites in England variously comprising one or more stone or posts flanking the entrance either in the end of the banks or in the terminals of the ditch. Burl (1969, 7) suggests that the function of these portal settings may have been to prevent the spreading of the bank-ends or as supports for a door or gate of some kind.
Timber cirles occupying all of the central area of the henge have been recorded at Woodhenge, Wiltshire, and Mount Pleasant IV, Dorset. Both are similar in form to the timber circles found elsewhere as single monuments and in henge enclosures. Woodhenge comprised six concentric rings, at Mount Pleasant there were only five rings. Whether these timber circles represent the remains of roofed buildings or simply freestanding uprights has been a matter of debate.
Single rings of posts, post rings, have been recorded at three sites in England, the most well-known being that at Arminghall, Norfolk, where there were eight large timbers set in a horseshoe formation with the open side directly in line with the entranceway into the monument. The large size of the timbers in this post ring is indicated by the presence of ramps in each of the postholes to facilitate the erection of the posts. Occasionally the presence of a post ring within a henge can be detected by aerial photography, as at Arminghall, Norfolk, and Bow Down, Devon.
Stone circles are also found within henges, and at least six such cases have been identified in England. Avebury contains at least three separate circles, the largest one being the outer ring of some 98 stones with two small circles near the centre of the monument. At Arbor Low, Derbyshire, the stones do not seem to have been set up to judge from the fact that no stoneholes have been found. Elsewhere the presence of stoneholes without stones suggests the former presence and size of the stone circles, as for example at Devil's Quoits, Oxfordshire.
The only possible four-stone setting known within a henge is at Mayborough, Cumbria. Groups of three large upright stones forming a cove have, however, been recorded at Avebury, Arbor Low, and Mount Pleasant IV.
Single or isolated monoliths have been recognized by the survival of the stone or the presence of stone holes at over six sites. The stone were generally large, in most cases over 2m high. At The Stripple Stones, Cornwall, the monolith lies in the centre of the monument. Elsewhere such stones lie off-centre but perhaps focal to other features, some of which may now have disappeared. At Mount Pleasant IV the stone uprights represent a second phase in the history of the monument and follow the disappearance of the timber circle. At Milfield South a large standing post near the centre of the monument may have had a similar role to the monoliths at other sites.
A rather irregular stone aligment comprising at least 11 uprights was found near the centre of Avebury, and at Maiden's Grave a post alignment represented by four postholes may be comparable.
Pits, mostly circular in outline and containing dark soil but little else have been found at several sites including Avebury and Coneybury, both in Wiltshire.
Burials have been recorded at six or more henges, but few of these graves seem to relate to the primary use of the monument. At Avebury a minimum of two very disturbed interments were discovered in the central area. At King Arthur's Round Table, Cumbria, a cremation trench of some sort lay within the monument, while at Woodhenge the burial of a child lay near the centre of the timber circle as was interpreted as a dedicatory deposit. At Gorsey Bigbury the burials lay in the ditch and were almost certainly secondary, as too were the burials at Arbor Low. Phosphate surveys at Maxey suggested that burials may also have been present within this monument.
Perhaps connected with the presence of burials are the round central mounds found in at least three henges, but again it is unclear whether they represent primary features. The only excavated example is at Maxey, Cambridgeshire, where it seems the mound was bounded by a continuous ditch. Its construction probably took place in several stages, but there was is no evidence for a burial having been made in or under the mound.
Other features within henges are rare, although mention may be made of the stakeholes found at Coneybury and Avebury and elsewhere, some of which may be of prehistoric date. Outliers have been recorded at henges elsewhere in Britain, but none are certainly known at sites in England.
Henges are generally classified into four main types according to the number of entrances and ditches they have (Atkinson in Atkinson et al 1951, 82, following Piggott & Piggott 1939, modified by Burl 1969, 4). Clare (1985) has suggested a wholly different scheme, but this covers many other classes of monuments and fails to distinguish clearly between them. The traditional classification is therefore adhered to here except that an additional type is added to provide for the classification of sites with more than two entrances:
I Single entrance, single bank, and, usually, a single ditch circuit. (eg. Gorsey Bigbury, Somerset)
IA Single entrance, single bank, and double circuit of ditches. (eg. Condicote, Gloucestershire; Arminghall, Norfolk)
II Two opposed entrances, single bank, and single ditch circuit. (eg. Maiden's Grave, Humberside; Devil's Quoits, Oxfordshire)
IIA Two opposed entrances, single bank, and two or more circuits of ditches. (eg. Thornborough central, North Yorkshire; Big Rings, Oxfordshire)
III Four opposed entrances, single bank, and single ditch circuit. (eg. Avebury, Wiltshire)
Specimen ground plans showing examples of each of the five main types are shown on Figure 1.
Henges were used for a variety of secondary purposes in addition to the possible imposition of later ritual monuments already discussed. At Maumbury Rings, for example the henge was remodelled as an amphitheatre in Roman times and later as a Civil War fort, while at Thwing, Humberside, the site became a defended settlement in late Bronze Age times. At Knowlton, Dorset, a church and churchyard was built within the henge in the medieval period. Early medieval and Saxon burials have been recorded from a number of other sites including Thwing and Milfield South.
The original purpose and function of henge monuments is not fully understood. The arrangement of banks and ditches is taken to preclude a defensive role, and because of this and the kinds of components found within the enclosure they are generally regarded as ceremonial or ritual monuments. The nature of such rituals cannot at present be determined. Insufficient evidence for burials exists to suggest a strong link with funerary rituals, and there is no firm evidence for the presence of astronomical alignments in either the design of the henge itself or any of the component structures.