A priestess over the age of 50, a Pythia was a priestess of the Oracle at Delphi. One day a month, she was placed upon a tripod. Later writers state that this tripod was located over a fissure, from which fumes would rise. After she was asked a question, the Pythia would then achieve an ecstatic state and produce the oracle, which must have been chaotic at best. The priests would then interpret these ramblings for the petitioners, often into poetic meter.
The receives its name from a surname of Apollo, the Pythian. He obtained this name through his defeating of the dragon Python, which was once the guardian deity of Delphi.
Plutarch. The Fall of the Roman Republic.
Oxford Concise Companion to Classical Literature. ed. Howatson and Chilvers. Oxford. New York, 1993.
Burkert, Walter. Ancient Mystery Cults. Harvard Press, 1987.