While we say that the Gallic Wars were written by Caesar, they were really written by the scribes. The thesis of this paper is that they used the third person singular to refer to Caesar, since they were taking down dictation and would not use “I/we,” as they were not the ones who had done the action. This use of the third person is attested to in Greek authors, and Caesar obviously was pleased with how it sounded; while he had the last word on the subject, it’s the scribes who deserve the credit for style.
"What’s with Caesar and the Third Person in the Gallic Wars?,"
New England Classical Journal: Vol. 48
Julius Caesar, Gallic War, scribes, dictation, Third person, stylistics