Coins are an unusually good way of preserving history. They are stamped with the images of rulers and significant persons, the precious metals in them do not corrode easily, and the value of precious metal coins means that people save them. In the case of the Gallic usurper Domitianus, the best evidence we have are two coins recovered from buried hoards, one of which was ignored for a century.
The 3rd century CE was a time of great unrest in the northwest Roman empire. Rome faced enemies on several fronts, as well as internal strife. The Crisis of the Third Century, as it is known to historians, included a 50-year period in which there were no less than 26 claims to the throne of the Empire, largely from officers of the military. Gaul and Britannia had formed the Gallic Empire and claimed independence from Rome; the current Roman emperor rarely challenged this, as the Gallic emperor usually bore the brunt of invaders from the north, making one less thing for Rome to worry about. The eastern edge of the empire had become the Palmyrene Empire, ruled by regent Zenobia, who later claimed the title of Empress and was defeated by Aurelian in 272 CE.
Several leaders claimed the rule of the Gallic Empire, five of whom were considered somewhat legitimate (though not by Rome itself, since none of them had been acclaimed by the Senate), and two of whom were usurpers. Domitianus was one of the latter.
Until the more recent coin was found, historians were unsure that Domitianus had ever even claimed the Gallic throne. The majority of what we know about him comes from two sources written a century after Domitianus died. Both sources together give us fewer than 30 words about his life and reign. Zosimus states, “Epitimius, Urbanus, and Domitianus, were suspected of committing treason [by Aurelian], and were immediately apprehended and punished.” Neither source mentioned him as emperor.
Some sources say that his predecessor, Victorinus, was killed by one of his soldiers after finding out that the emperor had been sleeping with the soldier’s wife. While it’s possible that Domitianus was that soldier, there’s no way to know for sure, unless more contemporary records are found. However it happened, Domitianus claimed the throne after the death of Victorianus in late 270 or early 271 CE, and probably took control of the mint at Trier (in what is now Germany.) It’s unclear if the portrait on the coin is even that of Domitianus; it looks very similar to the coins minted for Victorinus. It’s possible the mint did not take time to create a new portrait, but simply made a few slight alterations and changed the name on the coin.
The first Domitianus coin was found in France in 1900; however, since little record had been kept of how it had been found, and there was no textual evidence for Domitianus ever having been emperor of the Gallic empire, it was assumed to be a modern forgery and dismissed. In 2003, metal detectorist Brian Malin was detecting in a field in Chalgrove, just outside Oxford. His family had recovered a small hoard from the field nearly 20 years before, but Malin was not convinced they had found everything. He came across a jar full of coins from the Roman era, which had fused together with the coil into a compact lump. He turned the hoard over to the Ashmolean Museum without attempting to separate the coins. As the experts at the museum worked their way through the coins, carefully freeing each one from the others, they discovered the Domitianus coin. Since this hoard had careful documentation, and the coin was found fused with other easily verified coins of the era, its authenticity was unquestioned. Even better, examination of the original French find confirmed that both coins had come from the same stamp. Both were authentic, and Domitianus regained his place in the line of Gallic rulers.
Both coins and their respective hoards seem to have been buried not long after Domitianus was overthrown by Tetricus. The Gallic Empire was reclaimed for Rome by the emperor Aurelian in 274 CE (as the Palmyrene Empire had been a few years earlier.) Aurelian suppressed the Gallic culture that had arisen, and it’s possible the coins were buried to protect them from raids or other military threats. It’s also possible that having a large amount of money was dangerous during such uncertain times, and the coins were buried to prevent them from being stolen. Regardless of how the coins ended up in the hoards, it is only due to their burial that we have any solid evidence of the emperor Domitianus.