Macrianus was the son of one of Valerians generals during his campaigns against the Persians. After Valerian was captured, the general Macrianus and the Praetorian Prefect Ballista rallied the troops and inflicted several defeats upon the Persian armies of Shapur, who retreated across the Euphrates. Inspired by this victory, they decided to march against Emperor Gallienus, while leaving the brother of Macrianus Junior, Quietus, in charge of the Eastern provinces. A large army under command of the general Aureolus met them and they were soundly beaten, both the emperor and his father died in the battle.