Marcus Fabius Quintilianus (Latin: [kᶣiːn.tɪ.li.ˈaː.nʊs];[1] c. 35 – c. 100 AD) was a Roman educator and rhetorician born in Hispania, widely referred to in medieval schools of rhetoric and in Renaissance writing.

Afer has been characterized as a more austere, classical, Ciceronian speaker than those common at the time of Seneca the Younger, and he may have inspired Quintilian's love of Cicero.

[5] The only extant work of Quintilian is a twelve-volume textbook on rhetoric entitled Institutio Oratoria (generally referred to in English as the Institutes of Oratory), written around 95 AD.

This work deals not only with the theory and practice of rhetoric, but also with the foundational education and development of the orator, providing advice that ran from the cradle to the grave.

An earlier text, De Causis Corruptae Eloquentiae ("On the Causes of Corrupted Eloquence") has been lost, but is believed to have been "a preliminary exposition of some of the views later set forth in [Institutio Oratoria]".

[7] Institutio Oratoria (English: Institutes of Oratory) is a twelve-volume textbook on the theory and practice of rhetoric by Roman rhetorician Quintilian.

[9] Rather than pleading cases, as an orator of his era might have been expected to do, he concentrated on speaking in more general terms about how sound rhetoric influences the education of the people.

[10] His rhetoric is chiefly defined by Cato the Elder's vir bonus, dicendi peritus, or "the good man skilled at speaking".

[18] Their views are further similar in their treatment of "(1) the inseparability, in more respects than one, of wisdom, goodness, and eloquence; and (2) the morally ideological nature of rhetoric.

The Middle Ages saw a decline in knowledge of his work, since existing manuscripts of Institutio Oratoria were fragmented, but the Italian humanists revived interest in the work after the discovery by Poggio Bracciolini in 1416 of a forgotten, complete manuscript in the Abbey of Saint Gall, which he found "buried in rubbish and dust" in a filthy dungeon.

But Quintilian is so consummate a master of rhetoric and oratory, that when, after having delivered him from his long imprisonment in the dungeons of the barbarians, you transmit him to this country, all the nations of Italy ought to assemble to bid him welcome... Quintilian, an author whose works I will not hesitate to affirm, are more an object of desire to the learned than any others, excepting only Cicero's dissertation De Republica.

[23]The Italian poet Petrarch addressed one of his letters to the dead to Quintilian, and for many he "provided the inspiration for a new humanistic philosophy of education".

Martin Luther, the German theologian and ecclesiastical reformer, "claimed that he preferred Quintilian to almost all authors, 'in that he educates and at the same time demonstrates eloquence, that is, he teaches in word and in deed most happily'".

It has been argued by a musicologist, Ursula Kirkendale,[25][page needed] that the composition of Johann Sebastian Bach's Das musikalische Opfer (The Musical Offering, BWV 1079), was closely connected with the Institutio Oratoria.

In addition, "he is often mentioned by writers like Montaigne and Lessing... but he made no major contribution to intellectual history, and by the nineteenth century he seemed to be... rather little read and rarely edited".

[26] However, in his celebrated Autobiography, John Stuart Mill (arguably the nineteenth-century's most influential English intellectual) spoke highly of Quintilian as a force in his early education.

He wrote that Quintilian, while little-read in Mill's day due to "his obscure style and to the scholastic details of which many parts of his treatise are made up", was "seldom sufficiently appreciated."

"His book," Mill continued, "is a kind of encyclopaedia of the thoughts of the ancients on the whole field of education and culture; and I have retained through life many valuable ideas which I can distinctly trace to my reading of him...".

[27] He was also highly praised by Thomas De Quincey: "[F]or elegance and as a practical model in the art he was expounding, neither Aristotle, nor any less austere among the Greek rhetoricians, has any pretensions to measure himself with Quintilian.

In reality, for a triumph over the difficulties of the subject, and as a lesson on the possibility of imparting grace to the treatment of scholastic topics, naturally as intractable as that of Grammar or Prosody, there is no such chef-d'œuvre to this hour in any literature, as the Institutions of Quintilian".