He was a thorough grammarian and a careful critic. His friends were in the habit of sending their works to him for a last revision, and it is by no means improbable that some of the delicate touches of Cicero's rhetoric may be due to his consummate taste and skill. He was himself an author, and wrote among other things an epitome of Roman history from the earliest time to his own. He was a ready and fluent letter-writer. But none of his writings are extant, except such few scraps of his epistles as are preserved in Cicero's answers to them.
The friendship between Cicero and Atticus began in their early boyhood. When Cicero first went to Athens—shortly after his defence of Roscius, and not improbably to escape the vengeance of Sulla—he found Atticus already established there, and for six months they, with Cicero's brother Quintus, who married the sister of Atticus, were constantly associated in study and in recreation. From that time Atticus was Cicero's closest and dearest friend, entering with the most vivid interest into all his plans and pursuits, lending him money, advising him in business, taking care of his property during his absences, and rendering counsel and aid in connection with the successive divorces of Terentia and Publilia. The correspondence between them now extant commenced only three years before Atticus returned to Rome, though it is hardly possible that they should not have exchanged letters previously.