Hortensius (Cicero)

Hortensius (Latin: [hɔrˈtẽːsi.ʊs]) or On Philosophy is a lost dialogue written by Marcus Tullius Cicero in the year 45 BC. The dialogue—which is named after Cicero's friendly rival and associate, the speaker and politician Quintus Hortensius Hortalus—took the form of a protreptic. In the work, Cicero, Hortensius, Quintus Lutatius Catulus, and Lucius Licinius Lucullus discuss the best use of one's leisure time. At the conclusion of the work, Cicero argues that the pursuit of philosophy is the most important endeavor.

While the dialogue was extremely popular in Classical Antiquity, the dialogue only survived into the sixth century AD before it was lost. Today, it is extant in the fragments preserved by the prose writer Martianus Capella, the grammarians Maurus Servius Honoratus and Nonius Marcellus, the early Christian author Lactantius, and the Church Father Augustine of Hippo (the latter of whom explicitly credits the Hortensius with encouraging him to study the tenets of philosophy).