Lucius Calpurnius Piso Frugi ( 261 AD) was probably a Roman general whom the imperial pretender Macrianus Major sent to suppress the governor of Achaia, Valens Thessalonicus. His existence is attested only by the unreliable Historia Augusta, which labels Piso as one of several usurpers who plagued the reign of Emperor Gallienus. While some historians grudgingly regard Piso as a historical figure, many reported details of his life, including his usurpation, are dismissed as fabrications. Background In June 260, Persian king Shāpūr I defeated and took Emperor Valerian captive at Edessa in Roman Mesopotamia. Valerian's son, Gallienus who had ruled jointly with his father, immediately became the sole Roman emperor. Gallienus, however, ruled the western portion of the empire and was far away from the threats of the East. Without Valerian in the east, the border populations and their legions felt vulnerable and elected their own emperors to guarantee they would have leaders against foreign threats. After the capture of Valerian, the legions of Pannonia threw off their allegiance to Gallienus and proclaimed Ingenuus, their military commander, emperor. After Gallienus put down this rebellion and returned to Italy to deal with the Alemannic invasion, another Roman general in Pannonia, Regalianus, would attempt to take the throne. Meanwhile, in Syria, Macrianus Major, one of Valerian's officers in charge of the treasury took advantage of the situation, gained the support of a key military commander, Balista, and claimed the throne for his two sons, Macrianus Minor and Quietus. In 261, after securing control of Egypt, Syria and Asia Minor, Macrianus Major and his son Macrianus Minor decided that they would travel west to Italy to confront and overthrow Gallienus. In their path to Italy, however, were the governors of the various Roman provinces with their military forces. One such governor remaining loyal to Emperor Gallienus was Valens Thessalonicus of the province of Achaea. Piso’s revolt To eliminate the threat of Valens and clear the track east, Macrianus Major and his son sent Piso to Achaea to kill Valens. Little, however, is actually known about Piso. The only source of information about Piso and his mission is the unreliable Historia Augusta. Piso is said to be a descendant of the gens Calpurnia and to have received the title Frugi for his severe virtues. The details of Piso's actions at the time are also unclear. Ultimately, Piso journeyed only as far as Thessaly where