Roman soldiers in chain mail are also shown on the column.
These are the earliest securely dated depiction I have been able to find of chain mail in a Roman context.
I have included the two details from it below, but I am not sure; it may be scale armour.
And it seems that Roman soldiers rather than auxiliaries are represented.
My feeling is that the armour is too schematically depicted for us to be certain either way.
Adrian also sees as an example of 'chain' mail the Augustan Vachères Warrior, but I feel that it shows a lorica squamata - the warrior is in any case a Gaul who would have been an auxiliary and not a citizen.
For centuries our only information about Roman chain mail came from it's depiction in art, for example this detail of the Ludovisi Sarcophagus.
The Ludovisi Sarcophagus dates from the mid 3rd century AD, and is sometimes linked to Hostilian, the son of Decius who was himself briefly emperor in AD 251.Although the sarcophagus depicts a Roman general fighting barbarians, Hostilian did not fight the Goths, but rather died of the plague at the age of 21.Decius and his elder son Herennius Etruscus died the same year fighting the Goths, so the iconography might have been better suited to them.Decius' body was never recovered, so the sarcophagus could not be his.I'm not sure what became of Herennius' corpse, but presumably it did not make it back to Rome as he never seems to be suggested as a potential occupant of the sarcophagus.Whoever it belonged to, the Ludovisi Sarcophagus is a fine depiction of the long chain mail shirt worn at the time, with sleeves that finish above the elbow.