A precipitous cliff on the W. of the Capitoline Hill at Rome, from which in ancient times persons guilty of treason were hurled; named after Tarpeia, a vestal virgin, who betrayed the city to the Sabine soldiers, then besieging Rome, on condition that they gave her what they wore on their left arms, meaning their golden bracelets; instead the soldiers flung their shields (borne on their left arms) upon her, so keeping to the letter of their promise, but visiting perfidy with merited punishment; at the base of the rock her body was buried.