Oracle (Lat. oraculum, from orare, to speak), in ancient religion, a revelation believed to be made by some divinity in reply to the questions of men; applied also to the place where such revelations were communicated. The responses were given cither by the mouths of priests or priestesses; or by other signs. Responses of the oracle at Dodona were given either by the movement of leaves, the noise of brazen vessels, or the murmuring of the waters of a fountain. Springs, fountains, grottoes, and caves, the waters of which were discovered to have delirious or narcotic effects, were selected to be the sites of oracles. At Didyma the vapor of the water affected both the priestess and the person who came to consult her; at Colophon the priest drank of the water of a secret well in a cavern; at Delphi the priestess, called the Pythia, delivered her utterances from a tripod placed over a chasm from which intoxicating vapors arose. In some of the oracles artificial fumigations were employed. Oracular responses were in general remarkable for obscurity and equivocation, yet they exerted great political as well as religious influence. The responses of the Pythia were not authoritative till they had been written and interpreted by the presiding officer.

Delphi, which was the common centre of all the oracles of Apollo, thus became the religious and political metropolis of Greece, and afterward extended its authority over the Romans. The Neo-Platonists referred the origin of oracles to demons, as did also the early Christians. The theurgists sought to revive them and to oppose their power to Christianity. Eusebius and others affirmed that they became silent at the birth of Christ, and assigned as the reason that Christ put an end to the power and the worship of Satan on the earth. - There were 22 oracles for the consultation of Apollo, the most important of which was at Delphi. (See Delphi.) The principal others were that at Abas in Phocis, which, though burned by Xerxes, continued to be held in repute as late as the reign of Hadrian; that of the Branchi-dae at Didyma, near Miletus, which was administered by a family having the hereditary gift of prophecy, received from Croesus as rich presents as that at Delphi, and was burned by the Persians, but continued to be consulted; that at Clarus, in the territory of Colophon; that at Ismenium, in Boeotia, the national sanctuary of the Thebans, which interpreted signs instead of speaking from inspiration; that at Patara, in Lycia, which was consulted only in winter, and where the prophetess was obliged to wait a whole night in the temple before making communications; and that at Telmes-sus, also in Lycia, the priests of which interpreted dreams and other marvellous events.

The most important oracles of Jupiter were at Olympia in Elis, and Dodona in Epirus. That at Olympia was chiefly consulted by those intending to take part in the Olympic games. That at Dodona was one of the most ancient and celebrated. The responses, in sounds produced by the rustling of the wind in an oak tree ("the speaking oak"), were interpreted in early times by men, but afterward by old women. Its sacred oaks were cut down and its temple demolished by the Aetolians in 219 B. C, but it was consulted until the 3d century A. D. There was also an oracle of Jupiter Amnion in Libya, which was first made known to the Greeks by the Cyremeans; it was in decay in the time of Strabo. The other divinities were consulted by oracles only on the special departments over which they presided. Thus, Ceres foretold at Patrre in Achaia the fate of sick persons by means of a mirror suspended in a well; Mercury was consulted at Pharse in Achaia, the person going away after a ceremony, and accepting the first remark that he heard from any one as the response of the divinity.

There was an oracle of Pluto and Proserpine near Nysa in Caria, at which priests divined concerning the remedies for illness by passing a night in a sacred grotto, where they often took their patients with them, who would themselves fall into a prophetic sleep. An annual festival was celebrated there, the young men driving into the cave a bull, which immediately fell dead. Heroes sometimes acted as mediators to reveal the will of Jupiter to men. The spot near Thebes where Amphiaraus was said to have been swallowed up was the seat of an oracular sanctuary. Birds never alighted there, and cattle never grazed in the neighborhood. After a fast the inquirers slept in the temple, and received the revelations in dreams. If they recovered, they were obliged to drop some money into the well of Amphiaraus in the interior of the shrine. Pausanias calls the oracle of Amphilochns, at Mallus in Cilicia, the most trustworthy known in his time. The oracle of Trophonius, at Lebadea in Bceotia, was held in the highest esteem until a very late period. Several days of preliminary purification were required.

The inquirer went into the cave of Trophonius, was received by two boys, bathed in the river Her-cyna, and drank of two wells, one of which made him forget all his former thoughts, and the other prepared him for the visions which he was about to have. He then descended by a ladder to the bottom of the cave, and various reports were made of what was there seen, and the responses of the priests were modified according to these reports. There were nu-erous oracles of Aesculapius, the most celebrated being that of. Epidaurus in Argolis. The principal Eoman oracles were those of Faunus in the grove of Albunea and on the Aventine hill, where the inquirer received his answer in sleep in prophetic visions; those of Fortuna, where the responses were given by lot; and that of Mars, which in early times existed at Tiora Matiena, and at which the revelation was given through a woodpecker.