Raphael Regius (or Raffaele Regio) (c. 1440 – 1520) was a Venetian humanist, who was active first in Padua, where he made a reputation as one of the outstanding Classical scholars, then in Venice, where he moved in the periphery of an elite group composed of a handful of publicly sanctioned scholars, salaried lecturers employed by the Serenissima itself: on the fringes of this elite world also moved the scholar-printer Aldus Manutius (Lowry 1979). The most famous achievement of Regius is his demonstration that the Rhetorica ad C. Herennium, or Rhetorica secunda, was not written by Cicero, a milestone in the development of textual criticism. His bitter rivalry with other scholars and scorn for the "semidocti" reflect familiar competitive strains in the sometimes vituperative temper of Renaissance humanism.
Regio, or Regius as he signed himself, was doubtless a pupil of Benedetto Brugnolo, a central figure among Venetian humanists, who headed the Scuola di San Marco and delivered daily lectures at the foot of the Campanile from 1466 until he died in 1502, "universally lamented and aged over ninety" (Lowry).
In his edition of Quintilian's Institutiones Oratoria ("Institutes of Oratory") Regius was the first to attempt corrections of the numerous errors ("depravationes") in Quintilian's text. In his treatise on the text of Quintilian, the Problemata (probably 1492), he laid out his methods in textual criticism, which offer "insights that are still valid and useful for the modern textual critic," though Regius depends more on his own rationalization ("ratio") for resolution of textual difficulties than on an appreciation of the relationships among manuscripts, for which a modern scholar would strive. Regius recognized how glosses could creep into a text and corrupt it.
- His oration In eloquentiam panegyricus was printed by Matthaeus Cerdonis in Padua in 1483.
- A modern discussion of the authorship of the Rhetorica ad Herennium is in the introduction to the Loeb edition, p. viiiff.
- Ducenta problemata in Quintiliani depravationis, printed by Bonetus Locatellus.
- Johan Schloemann, reviewing Dopp 1999, (Bryn Mawr Classical Review 2001).
- Martin Lowry, 1979. The World of Aldus Manutius (Ithaca: Cornell University Press)
- M. Winterbottom, 1999. "In praise of Raphael Regius" in Siegmar Döpp (editor), Antike Rhetorik und ihre Rezeption. Symposion zu Ehren von Professor Dr. Carl Joachim Classen... (Stuttgart: Steiner)
- J. J. Murphy and M. Winterbottom, "Raffaele Regio's Quaestio Doubting Cicero's Authorship of the Rhetorica ad Herennium: Introduction and Text", in Rhetorica 17 (1999), pp 77–87.
- Pierre Maréchaux, « L’arrière-fable : la préface de Marot à la Métamorphose et les commentaire latins d’Ovide ». Clément Marot « Prince des poëtes françois » 1496-1996. Actes du Colloque international de Cahors en Quercy 21-15 mai 1996 réunis et présentés par Gérard Defaux et Michel Simonin. Paris, Champion, 1997, pp. 77-92 [on Marot and Regius].
- Pierre Maréchaux, « Regius (Regio Raffaele) (1440–1520). Centuriae latinae. Cent une figures humanistes de la Renaissance aux Lumières offertes à Jacques Chomarat. Genève, Droz, 1997, pp. 657-665.
- Pierre Maréchaux, « D’un sens à l’autre : Continuité et rupture à travers les commentaires des Métamorphoses d’Ovide du XIVe siècle au XVIe siècle ». Thèmes et figures mythiques, l’Héritage classique, Cahiers TEXTUEL n°33, septembre 1997, pp. 19-31.