Legio II Herculia: one of the legions of the later Roman empire. Its name means "the legion dedicated to Hercules".
This legion was created by the emperor Diocletian (284-305). It was called after Diocletian's colleague, the emperor Maximianus, who often called himself Herculius, "the man like Hercules". The date of the creation is unknown, but was probably at the beginning of the joint reign of the two emperors. Together with I Iovia, which seems to have been the twin of II Herculia, it was stationed in the newly created province of Scythia (near the mouth of the Danube), where dedications to Mithras have been found neat Troesmis. This unit was still there when the text known as the Notitia Dignitatum (a list of magistracies and army units) was composed (c.400).
Another dedication to Mithras by legionaries of II Herculia has been excavated at Sitifis (modern Setif in Algeria), so the unit or a subunit must have been transferred at least once.