The name of the cave was coined in 1608 by the painter Caravaggio,[1] who was shown the grotto by the mathematician, antiquarian and archaeologist Vincenzo Mirabella. It refers to the tyrant Dionysius I of Syracuse. According to legend, Dionysius used the cave as a prison for political dissidents, and by means of the perfect acoustics eavesdropped on the plans and secrets of his captives. Another legend claims that Dionysius carved the cave in its shape so that it would amplify the screams of prisoners being tortured in it.[citation needed] The sound-focusing effect can no longer be heard because access to the focal point is no longer possible. The visitors of the cave can however still hear the echo while they are in the Ear of Dionysius.[citation needed]

Because of its reputation for acoustic flawlessness, the Ear of Dionysius has also come to refer to a type of ear trumpet that has a flexible tube. The term 'Ear of Dionysius' can also refer to surveillance, specifically for political gain.[citation needed]