SIR, The remains of ancient Monmouth are constantly arising from underground but the discovery of an upstanding medieval building hidden inside the Masonic Temple, off Monk Street, is even more remarkable (last week's Beacon). However, this time it was not archaeologists who can take the credit for the unearthing but Bill Hall, whose wife Jeana was recently mayor of Monmouth. Bill noticed structural anomalies, including arrow slots, in the walls and carried out a close survey and study. Becoming convinced that he had recognised a medieval defensive building, he called us in and eventually Cadw became involved. The building must be part of the town's stone defences of which Monnow Bridge was a part – constructed around AD1300 – and which followed deep ditches and earth ramparts. Most of the town walls and gates are long gone, which makes the discovery even more exciting. Monmouth should be extremely grateful to Bill, whose quiet academic research has made such a significant addition to the history of our town. Stephen Clarke (Monmouth)