Historical reference: Do not rely on this information. It is very old. About this collection
Gallienus, Publius Licinius (Roman Emperor 260 - 268 A.D.), was the son of Valerian, who made him his colleague in the government. When his father was imprisoned by the Persians, the son lost all energy, and reigned only in Italy, the rest of the empire being governed by different generals, who earned the name of the Thirty Tyrants. Gallienus was murdered while besieging Milan.