The gens Tarpeia was a minor patrician family at ancient Rome. Only a few members of this gens are known, and the Tarpeii vanish from history after the early Republic. The Tarpeian Rock, a promontory on the Capitoline Hill, from which those condemned for treason were thrown to their deaths, is said to have been named after Tarpeia, the archetype of all Roman traitors.[1] There seems to have been a senatorial family of this name in imperial times.
The nomen Tarpeius belongs to a common class of gentilicia formed using the suffix -eius. Such names are typical of Sabine gentes, perhaps explaining the association of the Tarpeii with the war of Romulus against the Sabines at the beginning of Roman history.[2]
The only cognomina associated with the Tarpeii of the Republic are Montanus and Capitolinus, both of which belong to a class of surnames derived from the names of places, in this case both probably referring to the original residence of the Tarpeii, on the Capitoline Hill.[3] The Tarpeii of imperial times bore common surnames such as Valens, powerful, and Faustus, fortunate.[4][5]