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a steep cliff on the western side of the Capitoline Hill, in ancient Rome. State criminals condemned to death were hurled from the Tarpeian Rock. According to one legend, the rock is named for Lucius Tarpeius, who was thrown from that cliff for opposing King Romulus. According to another version, the rock is named after Tarpeia, daughter of the Capitoline Hill fortress commander Spurius Tarpeius, who was declared a traitress because she admitted Sabine forces into the fortress.