The monument, which is located close to a medieval fen bank enclosing marine silts which were probably taken in from the fen in the early 12th century, includes a moated site incorporating two enclosures on a line north-south and, adjoining this, to the north and east of the northern enclosure, the remains of part of a field system of medieval type. Rigbolt House is identified as the site of a cell of Sempringham Priory. The two enclosures, which are conjoined, are both sub-rectangular in plan, the northern enclosure being the larger of the two, with overall maximum dimensions of approximately 200m north-south by 160m east-west, and the southern enclosure having dimensions of approximately 136m east-west by 100m north-south. The central island of the northern enclosure is bordered on the north and west sides by a ditch measuring from 10m to 14m in width, and from 1m to 1.8m in depth. The southern enclosure is defined on its west side by the continuation southwards of the western arm, and on its north and east sides by a moat ditch which branches from the western arm and separates the two enclosures. The western arm narrows towards the southern end, where it has been modified to function as a drain and feeds into a brick culvert, whereas the eastern arm is a slightly broader feature, approximately 15m wide. All these parts of the moat, except for the eastern arm of the southern enclosure, are intermittently wet at the bottom. The moat probably continues around the southern side of the southern enclosure, although it is obscured here by a modern drainage ditch which runs alongside the adjoining bank. A part of the northern arm of the moat around the northern enclosure has been cleaned out near its eastern end to make a pond, and a length of up to 20m beyond this, at the eastern end itself, has been filled in, although it survives as a buried feature which is visible in air photographs. The eastern arm adjoining this has also been filled in, although it, too, will survive as a buried feature. A slight rectilinear scarp in the ground surface at the southern end of the projected line probably indicates the internal angle of the moat at the south eastern corner. The western arm of the moat around the northern enclosure is interrupted by a causeway across the northern end, and the northern arm is crossed by a causeway of recent construction. The central island of the northern enclosure contains several earthwork features, some of which probably relate to manorial or monastic buildings which once occupied the site. A bank approximately 56m in length, l9m wide and up to 0.8m in height runs westwards from a garden wall north west of Rigbolt House, which stands east of centre on the central island. To the south of this bank, around the west and south sides of Rigbolt House, is a low, rectilinear terrace approximately 0.5m in height and measuring c.40m on each side, north-south and east-west. In the north east corner of the southern enclosure, the upper edge of the moat ditch shelves internally to form a shallow, sub-rectangular bay, measuring approximately 22m north-south by 18m east-west, with traces of a bank around the west and south sides. A paddock adjoining the moated site on the north east side contains a series of parallel east-west ditches, visible as slight, linear hollows approximately 0.3m deep, alternating with low banks approximately 14m wide and up to 0.4m high above the prevailing ground level. These features are part of a system of field strips and drainage ditches known as dylings, and similar earthworks, although less well defined, can be seen immediately to the north of the moated site. The remains of the field system can be seen in aerial photographs to continue eastwards for approximately 500m across modern fields which are under plough, but the remains which are in ploughland are not included in the scheduling. In the 13th century, Rigbolt manor was held by the de Rye family from the Bishop of Lincoln, and in c.1280 Ranulph de Rye granted it, with its manorial chapel of St Mary, to Sempringham Priory, a foundation of the Gilbertine order. Thereafter, the manor continued as a cell and grange of the Priory until the dissolution. Part of a medieval structure, interpreted as a chapel, was still standing on the moated site in 1793, as part of a farmhouse, but this was demolished some time before 1816, when the present Rigbolt house was built. Many human bones were said to have been found nearby. Rigbolt House, which is Listed Grade II, is excluded from the scheduling, as are the farm buildings which occupy part of the eastern side of the site, all track and yard surfaces, paths, an oil tank, lamp posts and clothes line posts in the grounds of the house, the garden wall and fence, a lawn tennis court to the south of the house, service poles, a pump house and pump adjacent to the northern arm of the moat, and all field boundary fences and gates, although the ground beneath all these features is included. Reasons for Designation A monastic grange was a farm owned and run by a monastic community and independent of the secular manorial system of communal agriculture and servile labour. The function of granges was to provide food and raw materials for consumption within the parent monastic house itself, and also to provide surpluses for sale for profit. The first monastic granges appeared in the 12th century but they continued to be constructed and used until the Dissolution. This system of agriculture was pioneered by the Cistercian order but was soon imitated by other orders. Some granges were worked by resident lay-brothers (secular workers) of the order but others were staffed by non-resident labourers. The majority of granges practised a mixed economy but some were specialist in their function. Five types of grange are known: agrarian farms, bercaries (sheep farms), vaccaries (cattle ranches), horse studs and industrial complexes. A monastery might have more than one grange and the wealthiest houses had many. Frequently a grange was established on lands immediately adjacent to the monastery, this being known as the home grange. Other granges, however, could be found wherever the monastic site held lands. On occasion these could be located at some considerable distance from the parent monastery. Granges are broadly comparable with contemporary secular farms although the wealth of the parent house was frequently reflected in the size of the grange and the layout and architectural embellishment of the buildings. Additionally, because of their monastic connection, granges tend to be much better documented than their secular counterparts. No region was without monastic granges. The exact number of sites which originally existed is not precisely known but can be estimated, on the basis of numbers of monastic sites, at several thousand. Of these, however, only a small percentage can be accurately located on the ground today. Of this group of identifiable sites, continued intensive use of many has destroyed much of the evidence of archaeological remains. In view of the importance of granges to medieval rural and monastic life, all sites exhibiting good archaeological survival are identified as nationally important. The moated site at Rigbolt House is of importance as a manorial site and as a cell and grange of Sempringham Priory, and its proximity to Newhall moated site, a grange of Spalding Priory less than 1km to the south in the neighbouring parish of Pinchbeck, is of additional interest for comparative studies of this class of site and for the study of the medieval landscape in this part of the Fenland region. The monument survives well, being undisturbed by cultivation and to a large extent unencumbered by later building. It will retain archaeological information concerning the construction of the moated site and the organisation and use of the site as a grange throughout the medieval period, and evidence of earlier land use will be preserved beneath the internal banks and raised surfaces. The adjacent earthworks will preserve evidence for farming practices in the area immediately around the moated site. {1}