Railway construction reveals a coin minted by a Roman officer who proclaimed himself 'emperor of the north' in Britain 1,700 years ago

For a brief period in the third century C.E., a Roman naval officer named Marcus Aurelius Mausaeus Carausius presided over Britain and northern Gaul as the self-declared “emperor of the north.”

Tasked with stopping pirate attacks in the North Sea, Carausius instead seized the raiders’ treasure for himself, attracting the ire of the Roman co-emperor Maximian. To escape punishment, he established a breakaway state in 286.

During his seven years in power, Carausius minted an array of coins “for propaganda purposes, emphasizing themes, such as local agriculture and wealth production, which would have been essential for Britain’s survival outside the Roman Empire,” historian Adam Rogers wrote for the Conversation in 2017. Now, one of these coins—a denarius dated to 287—has resurfaced along the route of a planned railway in England.

Archaeologists unearthed the ancient coin while conducting excavations in Bedfordshire and Cambridgeshire, two neighboring counties in the east of England. Per a statement from the East West Railway Company, the team also found a late Iron Age vase, pottery fragments, and a second coin believed to date to the reign of either Antoninus Pius (138 to 161) or Marcus Aurelius (161 to 180).

“We know from other projects nearby that this part of Britain has a rich archaeological landscape, and we weren’t disappointed,” Mike Court, historic environment lead at East West Rail, tells Fox News Digital’s Andrea Margolis. “By the time we [are] finished, we expect to find archaeology from most, if not all, periods of British history and prehistory.”

The East West Rail is an ambitious project that will connect Oxford and Cambridge. Ahead of construction, archaeologists have examined 1,000 trial trenches, or designated areas that experts can rapidly assess to detect historically significant artifacts. Over the next two years, the company notes on its website, researchers plan to survey an additional 6,000 trial trenches.

“We’re working closely with landowners and local communities throughout the process to minimize disruption, keep people informed and restore land as closely as possible to its previous condition once works are complete,” says Jorn Pace, a program manager at East West Rail, in the statement.

Previous finds made by the East West Rail team include a 4,000-year-old Bronze Age cemetery, Jurassic and Cretaceous period fossils, and ancient brooches and bracelets. As Court explains to Fox News Digital, the newly unveiled Carausius coin is “particularly interesting” because it allows the archaeologists to date their discoveries to a specific era in British history. Other evidence found nearby suggests that the site was once home to a Roman settlement.

Details of Carausius’ life are sparse, limited mainly to “problematic textual sources, a few propaganda images, and limited text on coins and medallions,” per the Conversation. Born in what is now Belgium, Carausius was “an obvious choice” to take control of the Classis Britannica, a Roman fleet based in Britain, biographer Simon Elliott told Military History Quarterly’s Zita Ballinger Fletcher in 2022. He’d previously helped Maximian, who was appointed senior co-emperor by Diocletian in 286, defeat attacks by Germanic tribes on land.

“However, Carausius proved so successful that many at court grew jealous and began to turn the emperor against him,” Elliott said. Eventually, the naval commander decided that he had no choice but to establish an empire of his own—no small feat at a time when the punishment for backing the wrong claimant was death.

Carausius’ rise to power probably involved “a long and gradual process of gaining support and influence, aided by Britain’s remote position on the edge of the empire and its growing dissatisfaction with the workings of Rome,” Rogers wrote for the Conversation.

According to the North Yorkshire-based Malton Museum, Carausius took deliberate measures to distinguish his realm from the Roman Empire, establishing mints in London and Colchester that produced “gold and silver coins of superb quality,” in contrast with the debased coinage of Diocletian and Maximian.

In 293, Maximian’s son-in-law Constantius dealt a decisive blow to Carausius, capturing the British-held settlement of Gesoriacum. That same year, Carausius was assassinated by a man named Allectus, who probably served as his finance minister. Allectus succeeded Carausius as the ruler of Britain, but his reign proved short-lived, too, with Constantius seizing control of the region in 296.

“Before Carausius’ usurpation, the imperial center was growing weary of troublesome Britain, but having committed to recapturing it from Carausius and Allectus (so as not to lose face), it was then not an option to leave in the short term,” Elliott told Military History Quarterly. “The revolt kept Britain on the imperial map for another century at least.”

This article was originally published on Smithsonian Magazine. Read the full story here: Railway Construction Reveals a Coin Minted by a Roman Officer Who Proclaimed Himself 'Emperor of the North' in Britain 1,700 Years Ago © 2026 Smithsonian Institution.