The coins are thought to have been hidden from barbarian invaders about 1,500 years ago. They were found by two brothers-in-law who were cleaning rubbish from the seabed in Alicante. The pair unearthed 53 intact gold coins reportedly in “a perfect state of conservation,” after laying untouched since the fourth century.
Luis Lens and Cesar Gimeno came across the spectacular discovery seven metres deep in the sea by the coastal town of Xabia.
Mr Lens told local media: “I thought I had found what looked like a 10 cent coin.
“It was in a small hole, like a bottleneck.”
But when he returned to his boat for further inspection of the artefact, he spotted “an ancient image, like a Greek or Roman face”.
The divers then returned to the site and spent two hours digging up the rest of the treasure using a corkscrew and a Swiss Army knife.
Jaime Molina from the University of Alicante said: “This is one of the largest sets of Roman gold coins found in Spain and Europe.
“It’s an exceptional archaeological and historical find since its investigation can offer a wealth of new information to understand the final phase of the fall of the Western Roman Empire.”
Experts from the University of Alicante have identified three coins that show Roman Emperor Valentinian I, seven coins showing Valentinian II, 15 of Theodosius I, another 17 of Arcadio and 10 of Honorius.”
Honorius, was emperor of the Roman Empire from 393 to 423 AD while Valentinian I is thought to have ruled from 364 to 375 AD.
READ MORE: AstraZeneca secures huge deal with UK start-up to produce new vaccine
The coins are set to be donated to a local museum to be put on display.
The bay of Portitxol in Xabia is well-known for having a mass of underwater archaeological remains.
Ceramic remain from different periods, anchors, amphorae cargoes, metallic material and elements used for ancient navigation, have all previously been discovered there.