The origin of his eager desire to be an orator, they tell us, was as follows. Callistratus the orator was going to make a plea in court on the question of Oropus,1
and the trial was eagerly awaited, not only because of the ability of the orator, who was then at the very height of his reputation, but also because of the circumstances of the case, which was notorious.
Accordingly, when Demosthenes heard the teachers and tutors agreeing among themselves to be present at the trial, with great importunity he persuaded his own tutor to take him to the hearing. This tutor, having an acquaintance with the public officials who opened the courts, succeeded in procuring a place where the boy could sit unseen and listen to what was said.
Callistratus won his case and was extravagantly admired, and Demosthenes conceived a desire to emulate his fame, seeing him escorted on his way by the multitude and congratulated by all; but he had a more wondering appreciation of the power of his oratory, which was naturally adapted to subdue and master all opposition. Wherefore, bidding farewell to his other studies and to the usual pursuits of boyhood, he practised himself laboriously in declamation, with the idea that he too was to be an orator.
He also employed Isaeus as his guide to the art of speaking, although Isocrates was lecturing at the time; either, as some say, because he was an orphan and unable to pay Isocrates his stipulated fee of ten minas,2
or because he preferred the style of Isaeus for its effectiveness and adaptability in actual use.
But Hermippus says that he once came upon some anonymous memoirs in which it was recorded that Demosthenes was a pupil of Plato and got most help from him in his rhetorical studies. He also quotes Ctesibius as saying that from Callias the Syracusan and certain others Demosthenes secretly obtained the rhetorical systems of Isocrates and Alcidamas and mastered them.