Lewes Priory is a part-demolished medieval Cluniac priory in Lewes, East Sussex in the United Kingdom. The ruins have been designated a Grade I listed building. History The Priory of St Pancras was the first Cluniac house in England and had one of the largest monastic churches in the country. It was set within an extensive walled and gated precinct laid out in a commanding location fronting the tidal shore-line at the head of the Ouse valley to the south of Lewes in the County of Sussex. The Priory had daughter houses, including Castle Acre Priory in Norfolk, and was endowed with churches and extensive holdings throughout England. In Lewes it had hospitiums dedicated to St James and to St Nicholas. In 1264, during the Battle of Lewes, King Henry III retreated with his forces to the Priory precinct which then came under attack from those of Simon de Montfort after his victory over Henry's army in battle. Henry was forced, in the Mise of Lewes, to accept the Council that was the start of Parliamentary government in England. The Lewes Priory Trust currently manages the site on behalf of Lewes Town Council who are the freeholder. The Priory is a nationally important historical site but an almost lost monument of mediaeval England, the buildings having been systematically demolished after the dissolution of the monasteries in the reign of Henry VIII. Some parts of the lesser buildings survive above ground, fenced off within a public park. The Priory has been the subject of academic and archaeological study since the mid-nineteenth century and a Heritage Lottery Fund grant in 2009 enabled repair of the surviving fabric, full public access and the provision of information panels interpreting the site and its history. Foundation Lewes Priory was founded by William de Warenne, 1st Earl of Surrey and his wife Gundrada, probably in 1081, following their visit to the Priory of Cluny in Burgundy in 1077. The dedication of the new Priory to St Pancras followed from the presence of a pre-existing Saxon shrine to that saint on the site. The cult of St Pancras was a strong link between Saxon England and Rome, having been introduced by Augustine in 597 at the behest of Gregory the Great. William de Warenne was acting under the auspices of a Cluniac Pope, Gregory VII. The ambition of the new work and piety of the new order