Legio I Illyricorum

This legion was probably founded by the emperor Aurelian after he had subdued the Palmyrene empire in 273. He used soldiers from the legions of the Danube that had fought in this campaign; they were to remain in the east as a non-oriental element that had no local loyalties. It was stationed at Palmyra, where it still was when the text known as the Notitia Dignitatum (a list of magistracies and army units) was composed (c.400).

A unit made up from soldiers of I Illyricorum and III Gallica was active in Egypt in 315-316. A comparable unit is known to have stayed at Syene in 323. In both cases, the commander was one Victorinus.