The `PYTHIA' label may need some explanation.
The myth tells how Apollon, the God of Wisdom, killed the powerful dragon-like monster Python, close to the village of Delphi in Greece. To commemorate this victory, Apollon founded the Pythic Oracle in Delphi, on the slopes of Mount Parnassos. Here men could come to learn the will of the Gods and the course of the future. The oracle plays an important rôle in many of the other Greek myths, such as those of Heracles and of King Oedipus.
Questions were to be put to the Pythia, the `Priestess' or `Prophetess' of the Oracle. In fact, she was a local woman, usually a young maiden, of no particular religious schooling. Seated on a tripod, she inhaled the obnoxious vapours that seeped up through a crevice in the ground. This brought her to a trance-like state, in which she would scream seemingly random words and sounds. It was the task of the professional priests in Delphi to record those utterings and edit them into the official Oracle prophecies, which often took the form of poems in perfect hexameter. In fact, even these edited replies were often less than easy to interpret. The Pythic oracle acquired a reputation for ambiguous answers.
The Oracle existed already at the beginning of the historical era in Greece, and was universally recognized as the foremost religious seat. Individuals and city states came to consult, on everything from cures for childlessness to matters of war. Lavish gifts allowed the temple area to be built and decorated. Many states supplied their own treasury halls, where especially beautiful gifts were on display. Sideshows included the Omphalos, a stone reputedly marking the centre of the Earth, and the Pythic games, second only to the Olympic ones in importance.
Strife inside Greece eventually led to a decline in the power of the Oracle. A serious blow was dealt when the Oracle of Zeus Ammon (see below) declared Alexander the Great to be the son of Zeus. The Pythic Oracle lived on, however, and was only closed by a Roman Imperial decree in 390 AD, at a time when Christianity was ruthlessly destroying any religious opposition. Pythia then had been at the service of man and Gods for a millennium and a half.
The rôle of the Pythic Oracle prophecies on the course of history is nowhere better described than in `The Histories' by Herodotus [HerBC], the classical and captivating description of the Ancient World at the time of the Great War between Greeks and Persians. Especially famous is the episode with King Croisus of Lydia. Contemplating a war against the upstart Persian Empire, he resolves to ask an oracle what the outcome of a potential battle would be. However, to have some guarantee for the veracity of any prophecy, he decides to send embassies to all the renowned oracles of the known World. The messengers are instructed to inquire the various divinities, on the hundredth day after their departure, what King Croisus is doing at that very moment. From the Pythia the messengers bring back the reply
I know the number of grains of sand as well as the expanse of the sea,The veracity of the Pythia is thus established by the crafty ruler, who had waited until the appointed day, slaughtered a turtle and a lamb, and boiled them together in a copper cauldron with a copper lid. Also the Oracle of Zeus Ammon in the Libyan desert is able to give a correct reply (lost to posterity), while all others fail. King Croisus now sends a second embassy to Delphi, inquiring after the outcome of a battle against the Persians. The Pythia answers
And I comprehend the dumb and hear him who does not speak,
There came to my mind the smell of the hard-shelled turtle,
Boiled in copper together with the lamb,
With copper below and copper above.
If Croisus passes over the Halys he will dissolve a great Empire.Taking this to mean he would win, the King collects his army and crosses the border river, only to suffer a crushing defeat and see his Kingdom conquered. When the victorious King Cyrus allows Croisus to send an embassy to upbraid the Oracle, the God Apollon answers through his Prophetess that he has correctly predicted the destruction of a great empire -- Croisus' own -- and that he cannot be held responsible if people choose to interpret the Oracle answers to their own liking.
The history of the PYTHIA program is neither as long nor as dignified as that of its eponym. However, some points of contact exist. You must be very careful when you formulate the questions: any ambiguities will corrupt the reply you get. And you must be even more careful not to misinterpret the answers; in particular not to pick the interpretation that suits you before considering the alternatives. Finally, even a perfect God has servants that are only human: a priest might mishear the screams of the Pythia and therefore produce an erroneous oracle reply; the current authors might unwittingly let a bug free in the program PYTHIA.