Publius Licinius Egnatius Gallienus entered the world around 218 AD, born into a wealthy senatorial family in Falerii, an ancient city in Etruria. His father Valerian rose to power as emperor in September 253, and the Senate immediately elevated Gallienus to the rank of Augustus. This marked the beginning of a joint rule that would define his early years. He married Cornelia Salonina about ten years before he ascended to the throne, establishing a household that produced three sons: Valerian II, Saloninus, and Marinianus. The family dynamics shifted rapidly when Valerian II died on the Danube, likely in 258, during a period of intense military pressure. Later, Saloninus was named co-emperor but met a violent end in 260 at the hands of General Postumus's army. Marinianus followed his father into death shortly after 268, killed by order of the new regime. Inscriptions connecting Gallienus to the Egnatii family suggest deep roots in the region, yet his exact birth date remains lost to history.
Military Campaigns Against Usurpers
Gallienus faced immediate challenges from within the empire itself, starting with Ingenuus, governor of Pannonia, who declared himself emperor between 258 and 260. While Valerian fought Persians in the East, Ingenuus exploited the power vacuum in the West. Gallienus reacted with speed, leaving his son Saloninus at Cologne under the supervision of Albanus and Postumus. He crossed the Balkans with a new cavalry corps commanded by Aureolus and defeated Ingenuus at Mursa or Sirmium. Ingenuus either committed suicide by drowning or was killed by his own guards after his capital fell. Around the same time, Regalian emerged as another claimant to imperial power in the Balkans. He held authority for six months before being killed when Roxolani invaders took the city of Sirmium. Some historians suggest Gallienus may have invited these barbarians to attack Regalian, though others dismiss this accusation entirely. The Roman army also had to deal with Macrianus Major and Lucius Mussius Aemilianus, two eastern usurpers who proclaimed their sons as emperors after Valerian's capture. Gallienus sent Aureolus against them, defeating the rebels in Illyricum during spring or early summer of 261. The Macriani leaders were killed, and their rebellion collapsed.The Crisis Of The Third Century