The Beau Street Hoard on display at the Roman Baths, Geni, Wikimedia Commons, CC BY-SA 4.0.
In 2007 archaeologists digging before a hotel was built in Bath found a block of Roman silver coins under a floor, 150 metres from the Roman Baths. It held 17,577 coins packed in eight leather bags.
In November 2007, archaeologists from Cotswold Archaeology were excavating on Beau Street in the centre of Bath, ahead of work on a new hotel, when they found a mass of corroded coins in a small pit under the floor of a Roman building, beside a wall. The site is only about 150 metres from the Roman Baths.
The coins had fused into a solid block weighing about 109 kilograms. Rather than dig them out on site, the archaeologists lifted the whole block, crated it and craned it out, so that it could be taken apart under laboratory conditions. Scans showed bags inside, and when conservators at the British Museum took the block apart they found that the coins had been packed in eight separate leather bags. Some of the leather had survived because copper in the coins had stopped it from rotting.
There were 17,577 silver coins in all, from a denarius struck for Mark Antony's legions around 32 BC to coins of about AD 274, when the hoard was buried. That was a time of crisis for the Roman Empire, when Britain was part of a breakaway state known as the Gallic Empire. It is the largest hoard ever found in a Roman town in Britain.
The hoard was declared Treasure, and the Roman Baths raised the money to buy it, with support from the Heritage Lottery Fund and donations from the public. The coins went on display at the Roman Baths in 2015, in the gallery about the people of Roman Bath, Aquae Sulis.
Written for Global Finds from the National Lottery Heritage Fund, Cotswold Archaeology, the BBC and other published accounts. Photo: the Beau Street Hoard on display at the Roman Baths, Geni, Wikimedia Commons, CC BY-SA 4.0.
Those four are for England and Wales, where the Portable Antiquities Scheme records finds and the Treasure Act decides what must be reported.
Scotland runs its own system, and every find is reportable there — not only treasure. Treasure Trove Unit ›
The Republic of Ireland is different again, and severely so. Searching for archaeological objects without the Minister’s written consent is a criminal offence carrying fines or imprisonment, and the definition is broad enough to cover coins, buttons and buckles of almost any age. Do not assume British rules travel with you. The law, from the National Museum ›
Northern Ireland is stricter still. The Treasure Act applies and finds go to National Museums NI within fourteen days, but any searching that involves digging — metal detecting expressly included — needs a licence, and licences are only granted for archaeological projects. National Museums NI ›
This site covers discoveries from all over the world, and so does the variation in the law — from a recording scheme that thanks you, to a criminal offence. Wherever you are searching, find out what applies there before you go, not after.