Tarpeia, in Roman mythology, daughter of the commander of the Capitol in Rome during the Sabine War. Traditionally, she offered to betray the citadel if the Sabines would give her what they wore on their left arms, i.e., their golden bracelets; instead, keeping to their promise, they threw their shields on her and crushed her to death. The story may have been an attempt to account for the Tarpeian Rock, a cliff on the Capitoline Hill over which murderers and traitors were thrown.