Hortensius or "On Philosophy" is a lost dialogue written by Marcus Tullius Cicero in the year of 45 BC. The dialogue is named after Cicero's friend, the speaker and politician, Quintus Hortensius Hortalus. Two other protagonists are Lutatius Catulus and Lucullus. This meeting takes place at Tusculum, in Lucullus' villa. In order to spread the wealth of Greek philosophy among the leading citizens of Rome, Cicero adapted and expanded upon Aristotle's Protrepticus Philosophiae (Introduction to Philosophy), one of the most famous and influential books of philosophy in the ancient world, inspiring its readers to appreciate a philosophical approach to life.
Augustine of Hippo, at the age of 11, was sent to school at Madaurus (now M'Daourouch), a small Numidian city about 19 miles south of Thagaste. It was there where he became familiar with Latin literature. During this period he read Cicero's Hortensius, which he wrote moved him to "an incredible ardor" for philosophy and described the work as leaving a lasting impression on him and sparking his interest in philosophy. Augustine preserves some of the work by quoting from it in many of his books.
- Aristotelous Protreptikos Philosophias (Aristotle's Introduction to Philosophy), edited and translated by D.S. Hutchinson & Monte Ransome Johnson, c. 2002, p. 2.
- Rabinowitz, W. G.: Aristotle's Protrepticus and the Sources of its Reconstruction, Berkeley, 1957.
- Encyclopedia Americana, v.2, p. 685. Danbury, CT: Grolier Incorporated, 1997. ISBN 0-7172-0129-5.
- Saint Augustine (Bishop of Hippo.) (2006). Confessions. Hackett Publishing. pp. 40–. ISBN 978-0-87220-816-2. Retrieved 25 August 2012.