The Temples and Cult of Asclepius by Robert Thom, 1957. University of Michigan Museum of Art, Gift of Pfizer Inc.
Every night for nearly a thousand years (500 B.C. – 500 A.D.), sick and afflicted pilgrims flocked to the Grecian Temples of Asclepius to take part of a ritual called incubation. The ancient kindly god of medicine was expected to visit them during a dream state and either heal or prescribe drugs, diet, and modes of treatment. Only requisites were that they should be clean and “think pure thoughts.” To show their appreciation, recipients of Asclepius’ favor caused votives (stone or terra cotta images of the afflicted parts which supposedly had been healed) to be made, suitably inscribed, and presented to be hung as testimony on the temple walls. More than 200 such temples existed.