A clay pot filled with bronze coins is displayed at the archaeological museum in Seville, Spain, on April 28. Nineteen of the pots were discovered by excavation workers in a park outside the city. (Gogo Lobato/Agence France-Presse via Getty Images)

Workers laying pipes in a park in southern Spain have dug up a 1,300-pound trove of Roman coins in what culture officials say is a unique historical discovery.

The Seville Archaeological Museum said the construction workers came across 19 amphoras, a kind of ancient pots, containing thousands of unused bronze and silver-coated coins dating from the end of the fourth century.

The coins are believed to have been recently minted at the time and had probably been stored to pay soldiers or others working for the Roman Empire.

Museum director Ana Navarro said the discovery Wednesday in the southern town of Tomares outside Seville is unique for Spain and of value that can’t be calculated.

She told reporters that the museum had contacted counterparts in Britain, France and Italy and that the find appeared to be one of the most important from the period.

The coins are believed to be from the fourth century and possibly were intended as pay for soldiers. Spanish officials couldn’t put a value on the 1,300-pound stash. (Jose Manuel Vidal/EPA)

The regional cultural department said Friday construction work in the park had been stopped while archeologists investigate further.

The clay pots, 10 of which were said to be unbroken, were found about three feet underground.

Navarro said the coins studied so far bear images of emperors Constantine and Maximian and with a variety of pictures on the reverse.

The cultural department said the museum had no similar coins in its collection. Once the find has been fully investigated, the pieces will be put on display in the museum, the department said.

The Romans began to conquer Spain in 218 B.C. and ruled until the fifth century.