Classicly

The De Amicitia, inscribed, like the De Senectute, to Atticus, was probably written early in the year 44 B.C., during Cicero's retirement, after the death of Julius Caesar and before the conflict with Antony. The subject had been a favorite one with Greek philosophers, from whom Cicero always borrowed largely, or rather, whose materials he made fairly his own by the skill, richness, and beauty of his elaboration, Some passages of this treatise were evidently suggested by Plato; and Aulus Gellius says that Cicero made no little use of a now lost essay of Theophrastus on Friendship.