The following text is from the original listed building designation:
1050 DOVER CASTLE
The Roman Pharos
TR 3241 1/48
I
AD 46. Built under the Emperor Claudius. This guided the Roman fleet round to the port of Richborough. In mediaeval times it was used as a belfry to the Church of St Mary Sub-Castro. 4 storeys, 3 being Roman and the top storey and remains of battlements mediaeval. An octagonal tower with originally vertical stepped walls rising in tiers set back each within the last, now almost smoothed. Rubble with a facing of green sandstone and tufa and levelled at an interval of 7 courses with a double course of brick set in hard pink mortar. Round-headed windows with a small recessed spy-hole inside them.
Listing NGR: TR3295958251

English Heritage, List of Buildings of Special Architectural or Historic Interest (Map). SKE16160.