The hoard of 81 gold coins found by builders working on the foundations of an old pub in the South Tipperary town of Carrick-on-Suir have gone on display at the National Museum of Ireland in Dublin. They’re part of a new exhibition, Airgead, a Thousand Years of Irish Coins & Currency, which covers the history of money, coin and note, from 10th century hammered coins to the crisp pressed coins of the 17th century to credit cards and Internet banking.

There are 77 guineas and 4 half guineas in the Carrick-on-Suir hoard, the earliest dating to 1664, the reign of King Charles II, and the most recent dating to the reign of William III in 1701. This was a nearly unprecedented find in Ireland. The only other comparable discovery was made in Portarlington, Co. Laois, in 1947, when more than 100 gold coins and some silver coins were found by three wood workers — Joe Clarke, Joe Maher and Mike Daly — who spotted a rabbit carrying a coin in its mouth and dropping it outside of its burrow. The rabbit was apparently cleaning its warren of pesky human treasure. The men started digging and found dozens of coins in a pile next to fragments from a wood box which once contained it. These coins were buried in the 17th century in an area where under Cromwell’s iron rule, Catholics were not allowed to be. National Museum experts believe the hoard may have been buried by an Irish Army treasurer when Cromwell invaded.

Research is ongoing on the newly-discovered Carrick hoard, but according to Eamonn Kelly, keeper of Irish antiquities at the National Museum, the 81 coins may have been collected by a Catholic merchant during the Penal Laws which were enacted starting in 1695 and continuing through the 18th century. These laws prohibited Catholics from, among many things, holding public office, marrying Protestants, serving in the military, voting, buying land, inheriting land from a Protestant and owning a horse worth more than £5. Under this kind of pressure, it might behoove a moneyed Catholic to start digging to keep his money safe from depredation governmental and otherwise.

The coins were not assembled haphazardly. Whoever collected them selected the best quality coins. Less pure coins from mainland Europe were in common circulation in Ireland during the 17th century. The guineas in the hoard are 91% gold, so dependably pure that they would have been accepted as currency anywhere in Europe and the Americas, an important asset if you’re part of a politically oppressed minority who might have to flee at a moment’s notice some day.

The guinea was not just minted starting with the restored Stuart monarchy; the Stuarts were directly involved in securing the gold. King Charles II, his brother James, Duke of York, and a group of London merchants set up the Royal African Company with the goal of monopolizing the trade in gold and slaves from West Africa, most notable the Guinea coast. Starting in 1663, the Royal Mint used West African gold from the Royal African Company in its coins. The Royal African Company even got to leave its mark on the coins made with its gold. Three of the Carrick-on-Suir coins — one Charles II guinea, one James II guinea and one William III half-guinea — bear the Elephant and Castle logo of the Royal African Company.

The value of the hoard has yet to be fully assessed. Some big numbers like 500,000 euro ($650,000) have been thrown around, but that’s unlikely. One coin, the 1691 William and Mary Guinea, is in “extremely fine” condition and is worth 9,300 euro ($12,000). If all 81 coins were worth that the hoard would be worth close to a million dollars, but we know that’s not the case. Once the value is determined, the finders — David Kiersey, Shane Comerford, Tom Kennedy, Shane Murray and Patrick McGrath — will receive an undisclosed percentage of it as a reward.

Both the Carrick hoard and the Portarlington hoard are on display in the Airgead exhibition. The Carrick hoard coins will be loaned to the South Tipperary Riding Museum in Clonmel, the local museum nearest where there hoard was found, for a display in the fall.