The Thornbury Treasure is a hoard of 11,460 copper alloy Roman coins, mostly radiated and NUMMI , ranging from 260 to 348, found in Ken Allen Gardens in Thornbury, South Gloucestershire, England, and digging a pond in March 2004 it was described as "the third largest of its kind" found in Britain.
The treasure was discovered by Ken Allen while digging a pond in his garden. The coins were in a rough gray vessel decorated with ware, 40-50 cm (16-20 inches) high, presumably from Caldicot, Monmouthshire, which had been damaged by the earth.
Allen reported the find and took it to the Bristol City Museum and Art Gallery, where it weighed 28.6 kg (63 pounds), and "it took two men to lift the bucket in which it was collected." For the most part, the coins were easily identified after drying and chemical treatment.
During the investigation, the coroner declared the treasure to be a treasure, and an appraisal committee subsequently estimated it at £40,000. The Bristol City Museum and Art Gallery purchased the hoard with funds from the Heritage Lottery Fund, the Headley Museums Treasure Acquisition Scheme, and other organizational funds.