[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.

[6] Eutropius states that Tetricus had to suppress rebellion when he first became emperor, which Mairat identifies with the usurper Domitian II, noting that Zosimus provides only that he rose to power at the beginning of Aurelian's reign, without providing the area of his rule, but that two coins minted in his name that have been discovered were doubtlessly made in the Gallic mints between 269-274, with the specifics of the coin suggesting a dating of c. mid 271.

Drinkwater goes on to state that such a position "must have required considerable ability, both administrative and military", arguing that he proved himself an able commander against the Germans, and concluding that "The last Gallic emperor should not be dismissed as a lightweight".

[15] Because Gallienus was unable to prevent the raids, Postumus rose up and declared himself emperor; at about the same time, he assassinated Saloninus, Gallenius's son and co-emperor, in Colonia (modern-day Cologne).

[1][12] Postumus focused on defending the Gallic Empire, and, in the words of the 4th-century Roman historian Eutropius, "restored the almost exhausted provinces through his enormous vigour and moderation.

Postumus was killed by his soldiers in 269 in Mogontiacum (modern-day Mainz) while putting down a revolt by the usurper Laelianus, because he would not permit them to sack the city.

[a][22][23][24][25] Little of his early life is known, however, he had become a senator and occupied the post of praeses provinciae (provincial governor) of Gallia Aquitania, a province in the southwest of what is now France, by 271.

[b][26][27][28] Because the motivation for his assassination was personal, rather than political, Victorinus's mother, Victoria, was able to retain power within the empire; as Drinkwater notes, she was unable to take the throne herself as a woman, and thus selected Tetricus as a candidate, having him appointed by the army after securing their support with large bribes;[21][28][4] he further mentions the possibility that Tetricus was related to Victoria and Victorinus, but states that there is no direct support for this.

[28][4] Drinkwater posits that, as he was governor of Gallia Aquitania, Victoria likely reigned for several weeks from Colonia before Tetricus assumed power, possibly issuing coins deifying Victorinus during this period.

[29] The Gallic Empire mirrored the Roman imperial administrative traditions, and as such each Gallic emperor adopted a Roman regnal title upon his accession; after becoming emperor, Tetricus adopted the regnal name and titles of Imperator Caesar Esuvius Tetricus Pius Felix Invictus Augustus Pontifex Maximus.

[36][37] The semi-fictional Historia Augusta, in its biography of emperor Aurelian, states that Tetricus elevated his son at an unspecified date, however, neither Aurelius Victor nor Eutropius mentions such an event.

[1][35] Tetricus moved the capital of the Gallic Empire from Colonia to Augusta Treverorum in late 271 in order to guard against the Germanic peoples.

[4][42][45][43] Some Roman sources including Aurelius Victor, Eutropius, the Historia Augusta, and Orosius report that Tetricus had already made a deal with Aurelian, offering to surrender in exchange for an honourable defeat and no punishment, quoting the ghost of Palinurus from Virgil's Aeneid 6.365: eripe me his, invicte, malis [it] ('pluck me out, O undefeated one, from these troubles').

[4][42][46][47] However, this is believed by modern historians to be a product of Roman imperial propaganda;[4][42][45] Aurelian, who was attempting to stabilise his fragile empire, benefited from the account that Tetricus had planned to betray his army, as his troops would then be less likely to rise up again.

Seven surviving coins feature his image on the obverse, with the reverses showing him riding a horse, him holding an olive branch and a scepter, as well as various depictions of deities standing, including: Aequitas, Jupiter, Laetitia, Pax, and Spes.

A rare quinarius (a silver coin) issued during his reign has a three-quarter facing image of Tetricus on the obverse and Victoria standing with her foot on a globe on the reverse.

[52] Most of the coins minted during Tetricus's reign were of low quality; his antoninianus contained so little silver content that imitations were easy to make, leading to the market being flooded with fakes, called barbarous radiates.