Saloninus was one of the sons of Gallienus and Salonina. After the death of his older brother Valerian II, he was made Caesar late in 258 A.D. and sent to oversee the western regions, aided by his praetorian prefect Silvanus and the governor of Germany, Postumus. In 260 A.D., the same year his grandfather was captured by the Sasanians, Postumus rebelled and besieged him at Cologne. He was made Augustus in 260 but within a few weeks or months of his accession he was captured and executed. According to Vagi, his coinage as Augustus is extremely rare, with perhaps fewer than 20 specimens known. -- Coinage and History of The Roman Empire by David L. Vagi