Quietus ascended the throne at the same time as his brother Macrianus following the capture of Valerian, the former emperor. However, after Macrianus and his army were unable to defeat the forces of Gallienus he saw his support base dissipate and he fled his post. The troops of Gallienus were able to track him down and execute him soon after thus ending his brief reign. Quietus survived him scarcely any more time before he, too, was located and executed.