The Tarpeian Rock is the southern side of the Capitolium hill. It takes its name from Tarpea, the daughter of the gatekeeper of the capitolium castle. According to the legend, Tarpea betrayed the city of Rome revealing to the Sabinians the secret passage to arrive to the Capitolium hill. After this revelation she was killed by the same Sabinians. To the memory of this event, according to the roman tradition all the traitors and killers were thrown away from this rock.