Servilia, the mother of Brutus, was a sister of Cato the philosopher, and Brutus had a higher esteem for him than for any other Roman, Cato being his uncle and afterwards becoming his father-in-law.

There was practically no Greek philosopher with whom Brutus was unacquainted or unfamiliar, but he devoted himself particularly to the disciples of Plato.

To the New and Middle Academy, as they are called, he was not very partial, but clung to the Old. He was therefore always an admirer of Antiochus of Ascalon, whose brother Aristus he had made his friend and housemate, a man who in learning was inferior to many philosophers, but who in good sense and gentleness vied with the foremost.

Empylus also, who is often mentioned by Brutus himself in his letters, and also by his friends, as a housemate of his, was a rhetorician, and has left a brief but excellent account of the assassination of Caesar, entitled Brutus.