P. C(assius?) Regalianus (died 268) was a Roman usurper against Gallienus. The main source of information is the unreliable Historia Augusta. Other sources are Eutropius, who calls him Trebellianus, and Aurelius Victor and the Epitome, which call him Regillianus. About his origin, the Tyranni Triginta says he was a Dacian, a kinsman of Decebalus. He probably was of senatorial rank. After the defeat and capture of Emperor Valerian in the east (260), the border populations felt insecure, and elec… (More on Regalianus)