Pausanias, an ancient Greek traveler, described as follows:
Before the Temple of Ceres at Patras, there was a fountain, separated from the temple by a wall, and there was an oracle, very truthful, not for all events, but for the sick only. The sick person let down a mirror, suspended by a thread till its base touched the surface of the water, having first prayed to the goddess and offered incense. Then; looking into the mirror, he saw the presage of death or recovery, according as the face appeared fresh and healthy, or of a ghastly aspect.
- Sadowski, Piotr (23 September 2009). From Interaction to Symbol: A systems view of the evolution of signs and communication. John Benjamins Publishing Company. p. 152. ISBN 9789027288905.
- Armand Delatte, La catoptromancie grecque et ses dérivés (1932)