Appius Annius Trebonius Gallus was a distinguished Roman general and politician who lived in the second half of the 1st century and the first half of the 2nd century in the Roman Empire. He led troops in the Year of Four Emperors, as well as aided in the suppression of the revolt of Gaius Julius Civilis.
Trebonius Gallus was born into the gens Annia and was a member of the venerable family of the Annii Regilli. Regilli means ‘Little Queen’. He was related to the Roman Senator Marcus Annius Verus, who was a brother-in-law of Roman Emperor Hadrian and father of the Roman Empress Faustina the Elder, wife of the Roman Emperor Antoninus Pius.Faustina the Elder was the mother of Roman Empress Faustina the Younger and aunt of Roman Emperor Marcus Aurelius. His father may have been Appius Annius Gallus, one of the Suffect Consuls of the year 67; based on his name, his mother may have been a noblewoman with the cognomen Trebonia.
In the year 69 Trebonius Gallus allied himself with Otho by participating in the assassination of then Roman Emperor Galba. He was then appointed a legatus, and with Vestricius Spurinna led the Othonan forces against the troops of Vitellius. The two generals took up a defensive position along the Po River near Mantua. Trebonius Gallus was to aid Spurinna and when Vitellius’ general Aulus Caecina Alienus, tried to storm Placentia. Little was needed for the defense of the city was fierce. When Caecina laid siege to Placentia, Trebonius Gallus hastened with a detachment of his army to the relief of the place. When Otho assembled his council, to decide upon how to engage the enemy further, Gallus advised him to defer engaging in any battle.