The legions of Magnentius and Decentius in Amida had been raised by the former usurper Magnentius (a general who usurped against Constantius in Gaul between 350 and 353) in his name and that of his brother. They were therefore a remnant of those disloyal troops, hence their stationing (a banishment) in the east. Their conduct at Amida would restore both their honour and reputation. The more familiar epithet of the Tenth legion was Fretenses or Fretenis (“of the sea strait” after a battle fought in 36 BC near the Strait of Messina) although there is no need to doubt Ammianus’ accuracy in ascribing this slightly different (or additional) epithet (Fortenses is later used of the legion in the Notitia Dignitatum).
The Superventores and Praeventores may have been light cavalry, or perhaps light infantry since they are included with infantry legions listed here. They may also have been mixed auxiliary units – several units of them are named in the Notitia Dignitatum. Ammianus adds that there “were also in the town the greater part of the comites sagittarii (household archers)” (18.9.4). Ammianus, therefore, names seven legions and, at 19.2.14, he does indeed reiterate that there were seven legions present in the city. The exact status and numbers of some of the units he names are unclear, however – he gives the total population of the besieged city as 120,000. Certainly there were men from three legions (the Fifth, Thirtieth and Tenth) as well as the usurper legions of Magnentius and Decentius. How strong these units would become important as the siege went on.
This episode was written by Murray Dahm.
Murray is an ancient and medieval military historian from New Zealand, living in Australia. He has written more than 100 articles on various aspects of ancient and medieval military history and other historical topics from all periods. He is the author of Macedonian Phalangite vs Persian Warrior, Athenian Hoplite vs Spartan Hoplite and Leuctra 371 BC, all from Osprey Publishing. He is a regular on the Ancient Warfare Podcast.