The nobiles (sg. nobilis) were members of a social rank in the Roman Republic indicating that one was "well known".^[1] This may have changed over time: in Cicero's time, one was notable if one descended from a person who had been elected consul.^[2] In earlier periods and more broadly, this may have included a larger group consisting of those who were patricians, were descended from patricians who had become plebeians via transitio ad plebem, or were descended from plebeians who had held curule offices.^[3]

The nobiles emerged after the Conflict of the Orders established legal equality between patricians and plebeians, allowing plebeians to hold all the magistracies; the state of being "known" was connected to the nobiles's rights to funeral masks (Latin: imagines) and actors in aristocratic funeral processions.^[4] However, the term is largely unattested to in the middle Republic, having been introduced in the late Republic as a description rather than a status.^[5] Earning such a mask required holding one of the qualifying curule magistracies.^[6]

These elections meant the republican nobility was not entirely closed.^[7] Nor in the republic did nobiles enjoy special legal privileges. In the later Republic, one who became noble was termed a novus homo (English: new man), an unusual achievement.^[8] Two of the most famous examples of these self-made "new men" were Gaius Marius, who held the consulship seven times, and Cicero. While wholly new men were rare, the political elite as a whole turned over as some families were unable to win elections over multiple generations and other families became more prominent, creating slow-moving and osmotic change.^[9]

The prestige of the nobiles was connected directly to their election to high office by the people.^[10] During the Roman Republic, the nobiles never held less than about 70 per cent of the consulships over longer periods; by the time of Cicero, the nobiles as a whole held more than 90 per cent of the consulships, a proportion "remarkably untouched by the most violent political crises".^[4] The narrowing of what made someone part of the nobiles occurred around the time of the constitutional reforms of Sulla with its "much larger senate with a proportionately smaller circle of elite senators... many new Italians in the Sullan senate, and the increased number of praetors" leading the elite to close ranks to preserve their prestige.^[11]

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 were also regarded as belonging to the Roman nobility.^[12] The term still referred to descendants of republican and triumviral consuls, but by the Antonines, most noble families had died out; one of the last were the Acilii Glabriones who survived into the 4th century.^[4]

• Cursus honorum