CIMMERIUM (anc. geog.), a place near Baiae, in Campania, where formerly stood the cave of the sibyl. The people were called Cimmerii; who living in subterraneous habitations, from which they issued in the night to commit robberies and other acts of violence, never saw the light of the sun (Homer). To give a natural account of this fable, Festus says, there was a valley surrounded with a pretty high ridge, which precluded the morning and evening sun.