“And he shall take the two goats, and present them before the Lord at the door of the tabernacle of the congregation. And Aaron shall cast lots upon the two goats; one lot for the Lord , and the other lot for the scapegoat. And Aaron shall bring the goat upon which the Lord’s lot fell, and offer him for a sin offering. but the goat, on which the lot fell to be the scapegoat, shall be presented alive before the Lord, to make an atonement with him, and to let him go for a scapegoat into the wilderness.” – (Leviticus 16:7-10).
The idea that the sins of the people might be transferred to a goat, which, driven into the wilderness to die, carried away the moral trespasses with which he was symbolically loaded, doubtless had much to do with the change which came over the complexion of the Great God Pan, when Christianity commenced to rewrite the ancient heathen mythology. Gently Pan, who harmed no one beyond creating terror, became first Satanic, and then, in the end, Satan himself. In the middle ages, men believed that the Evil One took the form of a goat on earth, when he wished to work his wicked will unseen of men in his true character. Therefore Satan gradually grew both horns and tail! – from The Masonic Goat
The ancient pagan Celtic peoples of Britian worshipped a goat headed deity – Cernnunos the horned god of the Wood. It has been suggested that the English legend of Herne the Hunter is an allusion to Cernunnos, though this seems doubtful as Herne is thought to be a survival of Saxon, rather than Celtic, beliefs and is first mentioned in 1597 in Shakespeare’s The Merry Wives of Windsor (Act 4, Scene 4). It is, however, possible that Herne is a much-diluted incarnation of Cernunnos absorbed into Saxon folklore. It’s Kentish link is further diluted by Margaret Murray’s claim in The God of the Witches (1931) that Herne is a very localized legend not found outside Berkshire and the regions of the surrounding counties into which Windsor Forest once spread.
Seán Mac Mathúna in his Evidence of worship of the Horned God in early Celtic London writes:
…that worship of the Horned God in London and the South-East of Britain would have been widespread before the Saxon’s drove our Celtic forebears from the area around 560 AD (even though the Celts by this time were largely Christians and the Saxons were Pagans). Thus, we can assume that from historical records, that London was Celtic (and therefore largely Welsh-speaking) until at least the 6th century AD. Evidence that worship of the Horned God was still widespread in the 7th century is found in an edict issued by the Pope in 669 AD. He had been forced to send a mission to southern England and led by Theodore the Greek, who became the new Archbishop of Canterbury. One of his first actions was to issue a series of laws that forbade pagan practices. One of the most famous of these concerned the wearing of animal masks and costumes during the Twelve Days of Yule:
Whoever at the kalends (first) of January goes about in the form of a stag, that is changing himself into the form of an animal, dressing in the skin of a horned beast, and putting on the head of a beast, for those who in such wise transform themselves into the appearance of a wild animal, penance for three years, because it is devilish.