PAUL PEARSON HAS ALWAYS BEEN fascinated with ancient human history, even though his professional area of interest is more like earth science and paleoclimate. Pearson, of Cardiff University in the United Kingdom, has indulged his interest in the Roman Empire for a long time, and in March 2022 published The Roman Empire in Crisis, 248–260: When the Gods Abandoned Rome, a book focused on a particularly challenging stretch of Roman history.

In the third century, the empire was plagued by a series of civil wars, economic turmoil, an empire-wide pandemic, and a succession of leaders and usurpers vying to rule the sprawling Roman world. Pearson didn’t expect to stumble on an ancient mystery as well. “It was while writing that book that I came across an interesting story of an obscure emperor who was believed to have been fake because he was based entirely on fake coins,” he says.