After microscopic examination, researchers realize the scratches on four ancient coins were simply due to normal wear and tear.

A team of researchers, after looking at four ancient coins under a microscope, realized the coins' scratches were simply due to normal wear in circulation.

A team of researchers examining four ancient coins in a laboratory realized the tiny specks on the coins weren't dust motes but rather scratches from the microscope's lens, a finding that has led them to speculate about a lesser-known emperor from Roman times.

The researchers, from the Swedish National Museum of Antiquities in Stockholm, said in a statement that they discovered the flubs after zooming in on images of the coins, which were minted during the reign of Emperor Valerian in the mid-third century A.D. in the province of Dacia on the lower reaches of the Carpathian Mountains, now part of Romania.

The coins bore the inscription "Sponsian," a name that has puzzled researchers for decades. Some believe it refers to a colleague of Valerian's, while others speculate it might be a fabrication by later coin collectors.

However, the new study, published in the journal Classical Numismatic Society Journal, suggests that Sponsian might have been a local military leader who assumed the title of emperor in the absence of a suitable candidate.

"We are placing Sponsian in the context of a provincial, military and political crisis, the outcome of which was the creation of an autonomous imperial personage in a period of anarchy," the researchers wrote.

The researchers noted that the empire was then embroiled in civil war, with Valerian fighting in the east against the Sassanid Empire, while a usurper, Aelius Catilius, threatened in the north.

Meanwhile, Dacia, a distant and heavily defended outpost, was left to fend for itself, dealing with the threat of invaders and an outbreak of plague.

"The empire was in chaos at the time, with civil war, a usurper in the north, and the main emperor fighting in the east," said one of the researchers, Jesper Ericsson. "We are placing Sponsian in the context of a provincial, military and political crisis, the outcome of which was the creation of an autonomous imperial personage in a period of anarchy."

As the researchers zoomed in on images of the coins, they realized that the tiny specks they had been attributing to dust motes were actually scratches from the microscope's lens. This finding led them to reexamine their hypothesis about the coins and the time period in which they were minted.

"We began to see that the coins were not in optimal condition, with several scratches and a generally poor surface," said one of the researchers, Helen Pearson. "This is normal wear and tear for coins that have been in circulation for so long."

The researchers also pointed out that the coins bore no mint mark, which was usually included on coins of the period, and that they were minted from an unusual metal alloy.

"In order to create a functioning economy in the province they decided to mint their own coins," Pearson said. "They may not have known who the actual emperor was because there was civil war. But what they needed was a supreme military commander in the absence of real power from Rome. He took command at a period when command was needed."

The researchers concluded that Sponsian was most likely a local military leader who assumed the title of emperor in order to maintain order and stability in Dacia during a time of great upheaval.

"Our interpretation is that he was in charge to maintain control of the military and of the civilian population because they were surrounded and completely cut off," Ericsson said.

The researchers' findings are sure to spark debate among numismaticists and historians, but they provide a new and intriguing perspective on a lesser-known chapter of Roman history.