The imaginifer was one of the signiferi

Signiferi

The signiferi of the Roman legions were the ranks entrusted with various tasks to do with standard-bearing. Early in the Roman Republic the single rank signifer performed all these tasks but later in the Empire the tasks became more specialist with different ranks created for specific tasks,...

in a legion

Roman legion

A Roman legion normally indicates the basic ancient Roman army unit recruited specifically from Roman citizens. The organization of legions varied greatly over time but they were typically composed of perhaps 5,000 soldiers, divided into maniples and later into "cohorts"...

 in the times of the Roman Empire

Roman Empire

The Roman Empire was the post-Republican period of the ancient Roman civilization, characterised by an autocratic form of government and large territorial holdings in Europe and around the Mediterranean....

, who carried the imago - the image - of the emperor. The imaginifer was added to the ranks of the legions when the Imperial Cult

Imperial cult (ancient Rome)

The Imperial cult of ancient Rome identified emperors and some members of their families with the divinely sanctioned authority of the Roman State...

 was first established during the reign of Augustus

Augustus

Augustus ;23 September 63 BC – 19 August AD 14) is considered the first emperor of the Roman Empire, which he ruled alone from 27 BC until his death in 14 AD.The dates of his rule are contemporary dates; Augustus lived under two calendars, the Roman Republican until 45 BC, and the Julian...

. The imago was a three dimensional portrait made from beaten metal. It was carried only in the leading cohort

Cohort (military unit)

A cohort was the basic tactical unit of a Roman legion following the reforms of Gaius Marius in 107 BC.-Legionary cohort:...

.