During the Roman Republic, nobilis ("noble", nobilitas, plural nobiles) was a descriptive term of social rank, usually indicating that a member of the family had achieved the consulship. Those who belonged to the hereditary patrician families were noble, but plebeians whose ancestors were consuls were also considered nobiles. The transition to nobilitas thus required the rise of a non-noble individual to the consulship, who was considered a "new man" (novus homo). Two of the most famous examples of these self-made "new men" were Gaius Marius, who held the consulship seven times, and Cicero.
The Second Samnite War (326–304 BC) was a formative time in the creation of this ruling elite comprising both patricians and plebeians who had risen to power. From the mid-4th century to the early 3rd century BC, several plebeian-patrician "tickets" for the consulship repeated joint terms, suggesting a deliberate political strategy of cooperation.
Scholarly attempts to define nobilitas have led to debates over the particulars of its usage in ancient sources. Fergus Millar points out that nobilis was a descriptive word as used in the Late Republic, and not a technical term for a restricted social group in the sense of peerage. Matthias Gelzer held that the term was reserved for descendants of consuls, and therefore reckoned that Munatius Plancus, consul designate for 42 BC, was the last man to qualify as an ancestor for a nobilis. P.A. Brunt, building on the view of Theodor Mommsen, assembled evidence of broader usage that suggests any curule office might grant the aura of nobilitas. The term is not found in the literature of the mid-Republic, and came into use long after the social and political changes that created "noble" plebeians.
During the time of Augustus, a nobilis enjoyed easier access to the consulship, with a lowered age requirement perhaps set at 32. Women who descended from Augustan consuls are also regarded as belonging to the Roman nobility. In the usage of Tacitus and Pliny Minor, a nobilis is a descendant of the Republican aristocracy. The meaning of nobilis then evolved during the Imperial period.
- E.T. Salmon, Samnium and the Samnites (Cambridge University Press, 1967), p. 217.
- Gary Forsythe, A Critical History of Early Rome: From Prehistory to the First Punic War (University of California Press, 2005), p. 269.
- Matthias Gelzer, Die Nobilität der römischen Republik (1912).
- Designated by Julius Caesar while dictator.
- Matthias Gelzer, in Hermes 50 (1915) 395ff., as noted by Syme, The Augustan Aristocracy p. 51, observing that "the notion was peculiar and vulnerable."
- P.A. Brunt, "Nobilitas and novitas," Journal of Roman Studies 72 (1982) 1–17.
- Fergus Millar, "The Political Character of the Classical Roman Republic, 200–151 B.C.," as reprinted in Rome, the Greek World, and the East (University of North Carolina Press, 2002), p. 126 online, originally published in Journal of Roman Studies 74 (1984) 1–19.
- Ronald Syme, The Augustan Aristocracy (Oxford University Press, 1989, 2nd ed.), pp. 50–52 online.
- Pliny, Panegyricus Traiani 69.5: illos ingentium virorum nepotes, illos posteros libertatis ("those grandsons of outsized men, those descendants of liberty").
- Adam Afzelius: Zur Definition der römischen Nobilität in der Zeit Ciceros. In: Classica et Mediaevalia 1, 1938, 40–94.
- Hans Beck: Karriere und Hierarchie. Die römische Aristokratie und die Anfänge des „cursus honorum“ in der mittleren Republik, Akademie-Verlag, Berlin 2005.
- Hans Beck: Die Rolle des Adligen. Prominenz und aristokratische Herrschaft in der römischen Republik. In: Hans Beck, Peter Scholz, Uwe Walter (eds.): Die Macht der Wenigen. Aristokratische Herrschaftspraxis, Kommunikation und „edler“ Lebensstil in Antike und Früher Neuzeit, Oldenbourg, Munich 2008, 101–123.
- Jochen Bleicken: Die Nobilität der römischen Republik. In: Gymnasium 88, 1981, 236–253.
- Klaus Bringmann: Geschichte der Römischen Republik. Von den Anfängen bis Augustus. Beck, Munich 2002.
- P.A. Brunt: "Nobilitas" and "novitas." In: Journal of Roman Studies 72, 1982, 1–17.
- Leonhard A. Burckhardt: The Political Elite of the Roman Republic. Comments on recent discussion of the concepts of „Nobilitas“ and „Homo Novus“. In: Historia 39, 1990, 77–99.
- Matthias Gelzer: Die Nobilität der römischen Republik. Teubner, Leipzig 1912.
- Karl-Joachim Hölkeskamp: Die Entstehung der Nobilität. Studien zur sozialen und politischen Geschichte der Römischen Republik im 4. Jahrhundert v. Chr. Steiner, Stuttgart 1987, ISBN 3-515-04621-6.
- Karl-Joachim Hölkeskamp: Conquest, Competition and Consensus: Roman Expansion in Italy and the Rise of the "nobilitas". InL : Historia 42, 1993, 12–39.
- Fergus Millar: The Political Character of the Classical Roman Republic, 200–151 B.C. In: Journal of Roman Studies 74, 1984, 1–19.
- R. T. Ridley: The Genesis of a Turning-Point: Gelzer's "Nobilität". In: Historia 35, 1986, 474-502.
- Richard J. A. Talbert: The senate of Imperial Rome. Princeton University Press, Princeton 1987.