were officers under the Roman emperors
who were sent to demand arrears of the annona
The regular collector was termed exactor;
the opinator was an extraordinary official sent to
coerce overdue supplies, and was for the army what the compulsor
was for other tribute. The name is probably derived
in the sense of aestimare,
because they assessed
the due amounted to. (Cod. 12, tit. 38, s. 11; Cod. Theod.
tit. 4, s. 26; Symmach. Ep.