Legio II Flavia Constantia: one of the legions of the later Roman empire. Its name means "the reliable Flavian legion", but the element constantia is also a reference to the emperor Constantius I Chlorus.
This legion was probably founded in 296 or 297 by the emperor Diocletian, together with I Maximiana, to defend the southern part of Egypt against neighboring tribes. They were stationed in the neighborhood of Cusas. The legion is called after Constantius I Chlorus, one of the emperors in the western half of the empire. At the same time, a mixed subunit of V Macedonica and XIII Gemina was transferred to Egypt.
In the age of Theodosius I (378-395), a second legion was created with the name Legio II Flavia Constantia Thebaeorum. Northern barbarians seem to have been included in the original unit, and Egyptian soldiers were included in the twin legion, which was stationed in Thessaloniki in Macedonia.