Tan Hill, also known by its Christianized name of St. Anne's Hill, lies just a few miles south of Avebury. It is here that the Tan Hill Festival on August 6th is held in honor of the sacred fire. This sacred fire, is the best-known of the countless communal fire rituals performed by the Celts in the first week of August. Related to the festival of Lammas, it takes place two days after the end of the Celtic tree month of Tienne.
A harvest festival, the Tan Hill Festival evolved from a Neolithic festival anciently observed there (210-18). It commemorates Tienne or Tan, theCeltic deity of holy fire. Tan Hill is derived from the Celtic god, Tanaris, the god of thunder to which name, originally, the lightning might have given rise and from hence was derived the name of the sacred fire.
In Cornish dialect, which is Celtic, Tan is fire, and to tine signifies to light. St Anne, the supposed Mother of the Virgin Mary and the patron saint of Brittany,owes her association with hills to the similarity of her name to a Celtic god Tan or Tein, or, as some say, to Santan, meaning Holy Fire.