The gens Horatia was an ancient patrician family at Rome. In legend, the gens dates back to the time of Tullus Hostilius, the third King of Rome. One of its members, Marcus Horatius Pulvillus, was consul suffectus in 509 BC, the first year of the Republic, and again in 507. But the most famous of the Horatii was certainly his nephew, Publius Horatius Cocles, who held the Sublician bridge against the army of Lars Porsena circa 508 BC.
The nomen Horatius is said to have been derived from the hero Horatus, to whom an oak wood was dedicated. The gens was certainly of Latin origin, although there was some uncertainty as to when they arrived at Rome. A legend relates that in the reign of Tullus Hostilius, the fate of the ancient city of Alba Longa was decided by combat between three brothers from that city and three from Rome. The historian Livy states that most sources assigned the Horatii to Rome, and their opponents, the Curiatii, to Alba Longa. The victory of the Horatii was a pretext for the destruction of Alba Longa, and the transfer of its noble families to Rome.
The Horatii favored the praenomina Publius, Marcus, Lucius, and Gaius.
The Horatii of the Republic bore the surnames Barbatus, Cocles, and Pulvillus. Of these, Barbatus and Pulvillus were family names, while Cocles appears to have been a personal cognomen, given to the hero of the Sublician bridge. Plutarchus supposes that it was derived from the Greek cyclops, because he had lost an eye, or because the shape of his face made it appear as if he had but one eye. Cocles is said to have been the nephew of Marcus Horatius Pulvillus, and if he left any issue, they do not seem to have carried on his surname. Other surnames appearing amongst the Horatii in later times may have been adopted by freedmen of the gens; the poet Quintus Horatius Flaccus was the son of a libertinus, and the cognomen Flaccus is not otherwise found amongst the Horatii.