Roman Bronze Coin of Tetricus I (about 1,751-1,754 years ago)

Gaius Pius Esuvius Tetricus was a Gallo-Roman nobleman who ruled as emperor of the Gallic Empire from 271 to 274 AD. He was originally the praeses (provincial governor) of Gallia Aquitania and became emperor after the murder of Emperor Victorinus in 271, with the support of Victorinus's mother, Victoria. During his reign, he faced external pressure from Germanic raiders, who pillaged the eastern and northern parts of his empire, and the Roman Empire, from which the Gallic Empire had seceded. He also faced increasing internal pressure, which led him to declare his son, Tetricus II, caesar in 273 and possibly co-emperor in 274, although this is debated. The Roman emperor Aurelian invaded in 273 or 274, leading to the Battle of Châlons, at which Tetricus surrendered. Whether this capitulation was the result of a secret agreement between Tetricus and Aurelian or that surrender was necessary after his defeat is debated. Aurelian spared Tetricus, and made him a senator and the corrector (governor) of Lucania et Bruttium. Tetricus died of natural causes a few years after 274.

The primary sources for the Gallic Empire are substandard.^[1] According to numismatist Jerome Mairat, the most reliable contemporary sources of the Gallic Empire, are Aurelius Victor and Eutropius, although they are brief and believed to rely upon the hypothetical lost Enmannsche Kaisergeschichte.^[2] Historians Nicholson and Casey second this, describing a key source of information as being "brief notices by late 4th-century Latin authors who depended for much of their information on the lost Kaisergeschichte (Enmann's History of the Emperors)".^[1] Mairat states that Zosimus and Zonaras both reveal key information regarding the Gallic Empire in short sentences, relying upon the mostly lost works of Dexippus;^[2] Nicholson and Casey state more specifically that another main source for Tetricus, in particular, is "scattered allusions" from Zomimus' first book. Nicholson and Casey further posit another source as being "information gleaned from the rather copious coinage minted by the Gallic emperors".^[1] Lastly, Mairat states that the imperial biographies of the semi-fictional Historia Augusta provide a wealth of details regarding the Gallic Empire,^[2] with Tetricus being listed as one of the "Thirty Tyrants" within;^[3] however, this work is generally unreliable, with Nicholson and Casey stating that it the biographies "interweave fact, invention, and an idiosyncratic sense of humour."^[1] For instance, the Historia Augusta states that Tetricus was recognized in Hispania, but modern historians have rejected this.^[4][5]