The gens Pomponia was a plebeian family at ancient Rome. Its members appear throughout the history of the Roman Republic, and into imperial times. The first of the gens to achieve prominence was Marcus Pomponius, tribune of the plebs in 449 BC; the first who obtained the consulship was Manius Pomponius Matho in 233 BC.
In the latter part of the Republic, it was common for various gentes to claim descent from the founding figures of Rome; the companions of Aeneas, Romulus, or those who came to Rome in the time of the kings. The Pomponii claimed to be descended from Pompo, one of the sons of Numa Pompilius, the second King of Rome, whose image appears on some of their coins. Several other gentes also claimed Numa as their ancestor.[i]
Pompo, asserted as the name of the ancestor of the Pompilii, does indeed appear to have been an ancient praenomen of Sabine origin. It was the Oscan equivalent of Quintus, a very common name. Numa's father is said to have been named Pompo Pompilius, and it is evident that the nomen Pompilius was itself a patronymic surname derived from Pompo. Pomponius appears to be derived from an adjectival form of that name, and the equivalent of the Latin nomen Quinctilius. Thus, it is reasonably certain that some ancestor of the Pomponii was indeed named Pompo, although the claim that he was the son of Numa may well be a later addition.
An alternative explanation suggested during the early nineteenth century, was that the name might be derived from an Etruscan root, Pumpu or Pumpili. In her History of Etruria, Mrs. Hamilton Gray supposed Pumpu to have been the name of Numa's mother, adopted as a surname according to a tradition common to the Etruscan and Sabine cultures.
The Pomponii used a wide variety of praenomina. The principal names were Marcus, Lucius, and Titus. A few of the Pomponii bore the praenomina Quintus, Publius, and Sextus. The illustrious family of the Pomponii Mathones favored Manius, and there are individual instances of Gaius and Gnaeus.
In the earliest times, the Pomponii were not distinguished by any surname, and the only family that rose to importance in the time of the Republic bore the surname Matho. On coins we also find the cognomina Molo, Musa, and Rufus, but none of these occur in ancient writers. The other surnames found during the Republic, such as Atticus, were personal cognomina. Numerous surnames appear in imperial times.