One of the oldest buildings in Caldicot, Llanthony Secunda Manor, was built around 1120 as a grange for monks from Llanthony Secunda Priory in Gloucester.
At around the same time, a religious centre may have been founded at Llanthony, on the site of the later Priory.
The Gloucester Harbour Trustees are the Competent Harbour Authority (CHA) for the tidal part of the River Severn from the Gloucester weirs (Llanthony & Maisemore) down to just below the Second Severn Crossing, on the Welsh side of the Severn Estuary (north of Denny Island) from the Second Severn Crossing as far as Goldcliff, and on the River Wye up to its tidal limit (Bigsweir).
1236 Maud de Lusignan (c. 1210 – 14 August 1241, buried at Llanthony, Gloucester), daughter of Raoul I of Lusignan, Comte d'Eu by marriage, and second wife Alix d'Eu, 8th Comtesse d'Eu and 4th Lady of Hastings, and had issue.
In 1135, after persistent attacks from the local population, the monks of Llanthony Priory in the Black Mountains, Wales retreated to Gloucester where they founded a daughter cell, Llanthony Secunda.