St Mary in Castro , Dover St Mary in Castro , or St Mary de Castro , is a church in the grounds of Dover Castle , Kent , south - east England . It is a heavily restored Saxon structure , built next to a Roman lighthouse which became the church bell - tower . St Mary serves the local population and the army , and is the church of the Dover Garrison . Location . Dover is a major port on the south - east coast of England , at a gap in the white cliffs near the narrowest point of the English Channel . Its proximity to mainland Europe has made it a key military , maritime and trade location for millennia . The Romans built forts here in c . AD130 and c . AD270 , and the town has fortifications from many eras since . The Romans also built two pharoses , possibly c . AD130 , on the Eastern and Western Heights above the gap in the cliffs . St Mary in Castro is on the Eastern Heights . Saxon period . 600 . There are records of a church being built ' within the castle ' ( Latin ' in castra ' ) by Eadbald of Kent in the 630s . However , it is unclear whether this means within the Saxon burgh ( usually dated to later than 630 ) on the Eastern Heights , or within the ruins of old Roman fortifications in the valley . The large , late - Saxon cemetery around the present church does suggest the existence of a c . 600 church , but not definitively . 1000 . Whether or not it had a predecessor , the present Saxon church was built on the Eastern Heights around AD1000 . It is immediately adjacent to the surviving eastern pharos , which was used as a source of spolia : Roman tiles can be still be seen in the church fabric , particularly in the window arches ( usually of stone ) , and flint and tile from the pharos is used throughout the church ' s walls . The plinth that projects out from beneath the church and on which it stands , however , is of new stone . The church is cruciform with a central tower the same width as the nave but broader than the chancel and transept s . The nave has no aisle s . The door arch is the earliest to survive in any standing church in England . Medieval rebuilds . The Early English vault and the altar recess in the nave ' s southeast corner of the nave were probably both added to the existing church at the end of the twelfth century . As part of his building works at the castle , in 1226 Henry III of England instructed that the church be repaired and twenty - one years later ordered the making of three altars and images , for and of St . Edmund , St . Adrian and St . Edward , along with an image of St . John the Evangelist . A new stage was added to the four surviving Roman stages ( out of a possible original eight ) of the pharos to turn it into a bell tower , along with a short passage to connect it to the church . In 1252 , three bells were cast at Canterbury to be hung in the pharos . In 1342 – 3 , three bells were sold out of St Mary in Castro to another St Mary ' s church , in the nearby village of Lower Hardres , for at least £4 . They were replaced in 1345 by two newly cast bells , weighing 4266 lb and 1078 lb , and costing £15 18s . 5¼d . Between 1426 and 1437 , works on the pharos cost £176 11s . 11½d and included five new stone windows in the medieval stage , which may have been rebuilt . Other works on the church included repainting between 1324 and 1334 by " John of Maidstone " , and over £36 spent on church and keep in 1494 , although the proportion spent on the church is unknown . The latter work was by Sir Edward Poynings , who may well have been deputising for Prince Henry , then the Castle ' s Constable . Neglect and restoration . From 1555 to 1557 the church was walled up as it was felt unsafe due to lack of repairs , though nineteen years later recommendations were made to repair the chancel in stone , glaze ( or reglaze ) the windows and provide seats for men to hear divine service . It took another six years , but in 1582 fourteen small chairs were at last bought . Public worship then lasted to 1690 , though burials of troops from the garrison in the surrounding churchyard continued for some time after that . The remaining ruin was turned into a storehouse and cooperage in 1780 , but a further collapse in 1801 led to its becoming a coal store by 1808 , and thus it remained until 1860 . That year began the first of two Victorian restoration s . The first lasted until 1862 and was carried out by George Gilbert Scott , and the second restoration for only a year in 1888 , by William Butterfield . Butterfield ' s restoration completed the tower and added mosaic work in the nave and a vestry , but was generally held to be less sympathetic than the first by Scott . Today . Today Saint Mary in Castro is still a thriving church serving the Army and local people , and is the Dover Garrison Church . Dover Castle Statutes . The Dover Castle Statutes of 1267 on display in Saint Mary in Castro offer a fascinating insight into life in Dover Castle during the medieval age . The Statutes demand order and discipline from the guards , with heavy penalties imposed on any who swear or brawl ; they lay - out explicit plans for ceremonies , religious or otherwise , and the ringing of bells ; and they detail procedures for deaths , festivals . A copy of the script can be found here Description of the present church . The 28 feet high arches at the east and west ends of the crossing appear to be original , and their west faces are outlined by strip work of projecting tiles . A tall round - headed , stone - faced doorway ( now blocked and with not much left of its original stripwork outline , but with its typically Saxon alternating horizontal and vertical slabs ) gave access to the nave from the south . Unusual double splayed round - headed windows pierce the nave ' s north and south walls , and Scott ( who found them during his restoration ) suggested there were another pair near the west end of the nave ' s side walls . He saw this pair of windows , and putlog holes in the walls for supporting timbers , as evidence for a west gallery , for which space needed to be left between that pair of windows and the west wall .