In April 2002, three metal detecters (John L. Jones, Richard Jones and Fred Edwards) found their lives in a field near Abergavenny, Monmouthshire: a scattered hoard of 199 silver pennies
The hoard contained coins of Anglo-Saxon King Edward the Confessor (1042-1066) and Norman King William the Conqueror (1066-87). The treasure probably predates the founding of Abergavenny nearby in the 1080s.
The treasure trove was heavily covered with iron deposits, including remnants of cloth, suggesting that the coins were originally stored in a cloth sack. It is unclear whether they were hidden intentionally or simply lost. Either way, their owner was poorer by a significant amount: sixteen shillings and seven pence (16 shillings seven pence, or £0.83) represented a few months' wages for most.
Anglo-Saxon and Norman coins form a unique historical source: each shows the place of minting and the person responsible for the money. People had easy access to a network of mints throughout England (there were none in Wales), and every few years existing money had to be reprinted with a new design. The king, of course, got a cut each time.
The Abergavenny treasure trove includes 36 identifiable mints, as well as some non-standard coins that cannot currently be found. Coins from the region's mints, such as Hereford (34 coins) and Bristol, are the most common, outweighing larger mints such as London and Winchester. At the other end of the scale are individual coins from smaller mints such as Bridport (Dorset) or more distant ones such as Thetford (Norfolk) and Derby.
Hoards from western Britain are rare, so many previously unrecorded combinations of mint, mint, and issue were formed in the Abergavenny hoard.
We will probably never know why these coins ended up in a corner of the field in Monmouthshire, but in addition to expanding our knowledge of coinage itself, they shed new light on monetary conditions in the area after the Norman Conquest.
Coins have been found covered with iron nodules, and many have stuck to each other. This distorted the coins and obscured important details. Removing this nodule by mechanical methods such as a scalpel would have damaged the silver, and chemicals could not move the iron.
The solution to the problem was found in an unexpected but quite modern tool: the laser. A laser is a light source that provides energy in the form of a very intense single wavelength wave with a narrow beam that travels only a few millimeters.
Because the laser light is single-color (in this case, infrared light was used), the beam will interact intensely with some materials, but hardly at all with others. This infrared source was better absorbed by the darker layer of corrosion than the metallic silver.
The laser successfully removed most of the iron crust, but first it left a very thin oxide film on the surface. When this was removed, the detail shown on the base coin was excellent; one could see the rough marks and polishing marks transferred to the coin from the original stamp, as well as the applied legend.