Note 005
Imperator (from which we have derived Emperor)
signified under the republic no more than general, and was
emphatically bestowed by the soldiers,when on the field of
battle they proclaimed their victorious leader worthy of
that title. When the Roman emperors assumed it in that sense,
they placed it after their name, and marked how often they
had taken it.
Note to Chapter 3 of DECLINE & FALL by Gibbon