The biographer Suetonius wrote about lives of teachers in his work On Famous Men Although most of the work is lost, one part that survives offers some information about a grammaticus

Lucius Orbilius Pupillus was born in Beneventum He was left an orphan when both his parents were killed on the same day by a treacherous plot of their enemies First he obtained a job as a menial servant for the town magistrates Then he joined the army, was decorated, and eventually was promoted to the cavalry When he had completed his years of service, he returned to his studies and thus filled an ambition he had had since boyhood

For a long time he lived as a teacher in his hometown, but then in his fiftieth year (the year of Cicero's consulship), he moved to Rome and taught...