From the National Heritage List for England: Details: The monument includes a Cluniac monastery situated on a low spur on the eastern bank of a tributary of the East Stour river, around 10km south east of Ashford. The monastery was founded in around 1142 by Robert de Vere and survives in the form of standing buildings, earthworks and associated below ground remains. Dedicated to St John the Evangelist, the priory was dependent upon the principal English Cluniac house, Lewes Priory in Sussex. The main claustral buildings lie towards the centre of the monument, arranged around a square, east-west aligned cloister yard. The standing parts are Listed Grade I and incorporate the western range, originally the prior's lodgings, and an attached, ruined fragment of the western wall of the mainly demolished church. Constructed during the second half of the 12th century, with some 14th and 15th century remodelling and additions, the two-storeyed, ashlar-faced buildings incorporate dressings and decorations of high architectural quality. A detailed building survey has indicated that the church, the remainder of which will survive in the form of buried foundations, was aisled and originally around 14.6m wide internally, with a projecting newel stair-turret between the nave and each aisle. Major restoration work carried out in 1913-14 included the addition of a large service extension to the east. The standing buildings are in use as a private dwelling and are therefore excluded from the scheduling, although the ground beneath is included. The demolished ranges of the main cloister will survive in the form of buried foundations and associated below ground traces in the areas to the east of the standing buildings. Further associated buried remains representing the gatehouse, any subsidiary cloisters and the monastic burial ground, can be expected to survive in the areas surrounding the main cloister. A group of impressive associated earthworks visible in the south western and north eastern parts of the monument represent at least two, now dry fishponds, (designed to supply the monastery with fresh fish), an extensive water management system and a number of demolished buildings. Horton Priory was dissolved in 1536. Soon afterwards many of the monastic buildings were demolished, and the western range reused as a secular dwelling. Garden landscaping and building work carried out in association with the major building restoration of 1913-14 will have caused some disturbance to archaeological features. A number of features are excluded from the scheduling; these are the private house known as Horton Priory, all associated outbuildings, barns, modern garden structures and features, the modern surfaces of the carpark to the north of the house, all hardstanding, tracks, paths and paving, and all modern fences and gates; the ground beneath all these features is, however, included. Reasons for Designation: From the time of St Augustine's mission to re-establish Christianity in AD 597 to the reign of Henry VIII, monasticism formed an important facet of both religious and secular life in the British Isles. Settlements of religious communities, including monasteries, were built to house communities of monks, canons (priests), and sometimes lay-brothers, living a common life of religious observance under some form of systematic discipline. It is estimated from documentary evidence that over 700 monasteries were founded in England. These ranged in size from major communities with several hundred members to tiny establishments with a handful of brethren. They belonged to a wide variety of different religious orders, each with its own philosophy. As a result, they vary considerably in the detail of their appearance and layout, although all possess the basic elements of church, domestic accommodation for the community, and work buildings. Monasteries were inextricably woven into the fabric of medieval society, acting not only as centres of worship, learning and charity, but also, because of the vast landholdings of some orders, as centres of immense wealth and political influence. They were established in all parts of England, some in towns and others in the remotest of areas. Many monasteries acted as the foci of wide networks including parish churches, almshouses, hospitals, farming estates and tenant villages. The Cluniac order had its origins in the monastic reformations which swept across continental Europe in the tenth century. The reformations which occurred were partly a response to the impact of Viking raids and attacks on established monastic sites in the preceding century but were also a reaction against the corruption and excesses which were increasingly noted amongst earlier establishments. The Cluniacs were amongst the most successful of the new reformed orders that developed. The founding house of Cluny in south-east France was established in AD 910. Here the community obeyed a stringent set of rules which, amongst other things, involved celibacy, communal living and abstention from eating meat. The ideals of the Cluniac reformers passed on to England in the tenth century. Influential Cluniac houses had been established in England by 1077. Once established, Cluniac houses were notable for the strong links they maintained both with the founding house of Cluny in France and also with other houses of their order. Most Cluniac houses in England were established near major towns and they particularly sought locations in valley bottoms within the protection of a nearby castle. Cluniac monasteries are notable for highly decorated, elaborate buildings. Cluniac houses are relatively rare, with some forty-four houses known in England, and all examples exhibiting good survival of archaeological remains are worthy of protection. Horton Priory survives well, despite some subsequent disturbance, retaining standing buildings of high architectural quality and impressive associated earthworks. The monument will also contain important archaeological and environmental evidence relating to the original use of the monastery.