The son Trebonianus Gallus got declared as Caesar and Succesor by his Father 251 AD.

Right after the proclamation he got his Youth Consecration (Princeps Invventvtis) together with Hostilianus.

Before beening 20 years old, after Hostilianus early dead, Trebonianus Gallus did promote his as co-emperor.

During their shared reign of the Roman Empire was invaded by the goths.  Cowardly both co-emperors chose to stay in Rome rather than confront the invasion themselves.

When the Goths invaded Moesia Inferior the new local Governor, Aemilian, did refuse to pay the tribute to them and succeeded to repel the Goths by slaughtering many and forcing the rest back across the Rive Danube.

The prestige of Aemilian’s victory was so great that his  soldiers declared him spontaneously emperor to oppose to Trebonianus Gallus and Volusianus.

 Alarmed by the news,  Trebonianus Gallus and Volusianus  asked for reinforcements from he future emperor Valerian. At the time Valerian was busy strengthening the empire’s defences on the along the River Rhine.

Because of Aemilian troops marching in rapid pace to Italy,  Valerians reinforcements could not arrive in time to provide military assistance.

Trebonianus Gallus and Volusianus troops where outnumbered against the much stronger forces of Aemilian. Worried of beeing slaughtered by Aemilians forces, their troops mutinied and killed Gallus and Volusianus