The pronaos, or forecourt, to which access is given by thirteen steps, contains twelve columns. The ceiling decorations were of great magnificence, and the columns of quite exceptional height. It was here that the suppliants waited for the oracle of Apollo. Oracular divination was the art of foretelling the future through the power of the god mediated by the observation of natural events or objects. Divination in some form or another has been known in all countries in all ages and spread throughout the Western world in the form of astrology.
Oracular divination rests on conclusions drawn on the basis of observation and interpretation.
In the case of divination based on observation, recourse is had to the examination of accidental phenomena interpreted by intuition. The soothsayer who examines the intestines of the sacrificial animal, its shoulder-blade or its footprints in ashes was obliged to take special measures to ensure the truth of the oracular pronouncement. The signs chosen for observation by the ancient Greek and Roman soothsayers included lightning, thunder, the night and call of birds and sacred fowls, as well as accidental phenomena such as the spilling of salt, sneezing or stumbling. One of the oldest oracles was that of Apollo at Delphi on the skirts of Mt Parnassus at the top of the gulf of Corinth. At first the oracle belonged to Gaia, the goddess of the earth.