Gold coin featuring Sponsian the firstImage source, BBC News
Image caption, The face of Sponsian the first, who was purged from history by experts in the nineteenth century. Researchers have now established that he was a lost Roman emperor.

Scientists say that an ancient gold coin proves the existence of a fictional Roman emperor.

A coin bearing the name of Sponsian and his portrait was found more than 300 years ago.

It was locked away in a cupboard and thought to be a fake.

Scientists say they have proof that it was in circulation over two thousand years ago.

Prof Paul Pearson said he was astonished by the discovery.

The emperor we have found is one. The experts thought he was a fake and wrote him off.

We think he was a part of history.

Ruins of Roman fortImage source, Paul Pearson
Image caption, The ruins of the Roman fort which was headquarters of the Roman military in Transylvania from where Sponsian ruled.

In 1713, a small group of coins were found. It was thought to be a genuine Roman coin until the mid-19th century, when experts suspected that they might have been made by forgers.

In 1863, Henry Cohen, the leading coin expert of the time at the Bibliothque Nationale de France, considered the problem for his great catalog of Roman coins. He said that they were not only'modern' fakes. Sponsian was dismissed from scholarly catalogues.

Prof Pearson was researching for a book about the history of the Roman empire when he saw photos of the coin. He thought it might have been caused by the coin being in circulation.

He contacted the Hunterian Museum at Glasgow University, where the coin had been kept locked away in a cupboard, asking if he could work with the researchers there.

The coins were examined under a microscope and found that there were scratches and that the patterns were consistent with jingles in purses.

The coins had been buried in the soil for hundreds of years and a chemical analysis showed that, according to the curator of coins.

Scratchmarks on coinsImage source, BBC News
Image caption, Under a powerful microscope, researchers saw scratch marks caused by the coins being in circulation

The question of who was Sponsian needs to be answered.

The researchers think that he was forced to be the emperor of the most distant and difficult to defend province of the Roman empire.

The Roman empire was cut off from the rest of the world in 260CE. There was a civil war and a plague.

Surrounded by enemies and cut off from Rome, Sponsian assumed supreme command during a period of chaos and civil war, protecting the military and civilians until order was restored.

He believes that he was in charge of the military and the civilian population because they were cut off from the outside world. They decided to mint their own coins to create a functioning economy.

The coins are different from the ones in Rome.

Civil war may have made them not know who the emperor was.

They needed a supreme military commander with real power. At a time when command was needed, he took command.

Once the researchers had established that the coins were authentic, and that they had discovered what they believed to be a lost Roman emperor, they were able to alert the researchers at the Brukenthal Museum. Baron Samuel von Brukenthal bequeathed it. At the time of his death, the Baron was studying the coin and the last thing he did was write a note.

Hunterian MuseumImage source, BBC News
Image caption, The coin was locked away in a cupboard at the Hunterian Museum because it was thought to have been a fake

Everyone at the Brukenthal museum classified their coin as a fake. When they saw the UK research, they changed their mind.

According to the interim manager of the Brukenthal National Museum, the discovery is of interest to the history of Transylvania and Romania.

If these results are accepted by the scientific community, they will mean the addition of another important historical figure in our history.

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