In ancient Roman religion and myth, Faunus was the horned god of the forest, plains and fields; when he made cattle fertile he was called Inuus. He came to be equated in literature with the Greek god Pan.
Faunus was one of the oldest Roman deities, known as the di indigetes. According to the epic poet Virgil, he was a legendary king of the Latins who came with his people from Arcadia. His shade was consulted as a god of prophecy under the name of Fatuus, with oracles in the sacred grove of Tibur, around the well Albunea, and on the Aventine Hill in ancient Rome itself.
Marcus Terentius Varro asserted that the oracular responses were given in Saturnian verse. Faunus revealed the future in dreams and voices that were communicated to those who came to sleep in his precincts, lying on the fleeces of sacrificed lambs. W. Warde Fowler suggested that Faunus is identical with Favonius, one of the Roman wind gods (compare the Anemoi).
Consorts and family 
A goddess of like attributes, called Fauna and Fatua, was associated in his worship. She was regarded sometimes as his wife, sometimes as his sister. As Pan was accompanied by the Paniskoi, or little Pans, so the existence of many Fauni was assumed besides the chief Faunus. In fable Faunus appears as an old king of Latium, son of Picus, and grandson of Saturnus, father of Latinus by the nymph Marica. After his death he is raised to the position of a tutelary deity of the land, for his many services to agriculture and cattle-breeding.
Faunus was known as the father or husband or brother of Fauna, and of Latinus by the nymph Marica (who was also sometimes Faunus' mother). Fauns are place-spirits (genii) of untamed woodland. Educated, Hellenizing Romans connected their fauns with the Greek satyrs, who were wild and orgiastic drunken followers of Dionysus, with a distinct origin.
The Christian writer Justin Martyr identified him as Lupercus ("he who wards off the wolf"), the protector of cattle, following Livy, who named his aspect of Inuus as the god who was originally worshiped at the Lupercalia, celebrated on the anniversary of the founding of his temple, February 15, when his priests (Luperci) wore goat-skins and hit onlookers with goat-skin belts.
Two festivals, called Faunalia, were celebrated in his honour—one on the 13th of February, in the temple of Faunus on the island in the Tiber, the other on the 5th of December, when the peasants brought him rustic offerings and amused themselves with dancing (Peck 1898).
A euhemeristic account made Faunus a Latin king, son of Picus and Canens. He was then revered as the god Fatuus after his death, worshipped in a sacred forest outside what is now Tivoli, but had been known since Etruscan times as Tibur, the seat of the Tiburtine Sibyl. His numinous presence was recognized by wolf skins, with wreaths and goblets.
Equation with Pan 
With the increasing Hellenization of literate upper-class Roman culture in the 3rd and 2nd centuries BC, the Romans tried to equate their own deities with one of the Greeks', applying in reverse the Greeks' own interpretatio graeca. Faunus was naturally equated with the god Pan, who was a pastoral god of shepherds who was said to reside in Arcadia. Pan had always been depicted with horns and as such many depictions of Faunus also began to display this trait. However, the two deities were also considered separate by many, for instance, the epic poet Virgil, in his Aeneid, made mention of both Faunus and Pan independently.
Later worship 
Faunus was worshipped across the Roman Empire for many centuries. An example of this was a set of thirty-two 4th-century spoons found near Thetford in England in 1979. They had been engraved with the name "Faunus", and each also had a different epithet after the god's name. The spoons also bore Christian symbols, and it has been suggested that these were initially Christian but later taken and devoted to Faunus by pagans. The 4th century was a time of largescale Christianisation, and the discovery provides us with evidence that even during the decline of traditional Roman religion, the god Faunus was still worshipped. In Gaul, Faunus was identified with the Celtic Dusios.
- For oracular Faunus, see Virgil, Aeneid vii.81; Ovid, Fasti iv.649; Cicero, De Natura Deorum ii.6, iii.15 and De Divinatione i.101; Dionysius of Halicarnassus v.16; Plutarch, Numa Pompilius xv.3; Lactantius Institutiones i.22.9; Servius on the Aeneid viii.314.
- Peck 1898
- Varro, De lingua latina vii. 36.
- W. Warde Fowler (1899). The Roman Festivals of the Period of the Republic: An Introduction to the Study of the Religion of the Romans. London: Macmillan and Co. p. 259. Retrieved 2007-06-07.
- Peck 1898.
- Hutton, Ronald. The Pagan Religions of the Ancient British Isles. (1991) Blackwell ISBN 0-631-17288-2. Page 260-261
- Ronald Hutton (1988) Antiquaries Journal
- Papias, Elementarium: Dusios nominant quos romani Faunos ficarios vocant, as quoted by Du Cange in his 1678 Glossarium mediae et infimae latinitatis (Niort: Favre, 1883–1887), vol. 3, online; Katherine Nell MacFarlane, "Isidore of Seville on the Pagan Gods (Origines VIII. 11)," Transactions of the American Philosophical Society 70 (1980), pp. 36–37.
- Peck, Harry Thurston, 1898. Harpers Dictionary of Classical Antiquities (On-line)
- Hammond, N.G.L. and Scullard, H.H. (Eds.) 1970. The Oxford Classical Dictionary (Oxford: Oxford University Press) ISBN 0-19-869117-3.