On the whole this agrees with what is met with in Ireland, where the Druids, though appearing in the texts mainly as magicians, were also priests and teachers.  Side by side with them were the Filid, “learned poets,"[1022] composing according to strict rules of art, and higher than the third class, the Bards.  The Filid, who may also have been known as Fathi, “prophets,"[1023] were also diviners according to strict rules of augury, while some of these auguries implied a sacrifice.  The Druids were also diviners and prophets.  When the Druids were overthrown at the coming of Christianity, the Filid remained as a learned class, probably because they had abandoned all pagan practices, while the Bards were reduced to a comparatively low status.  M. D’Arbois supposes that there was rivalry between the Druids and the Filid, who made common cause with the Christian missionaries, but this is not supported by evidence.  The three classes in Gaul—­Druids, Vates, and Bards—­thus correspond to the three classes in Ireland—­Druids, Fathi or Filid, and Bards.[1024]

We may thus conclude that the Druids were a purely Celtic priesthood, belonging both to the Goidelic and Gaulish branches of the Celts.  The idea that they were not Celtic is sometimes connected with the supposition that Druidism was something superadded to Celtic religion from without, or that Celtic polytheism was not part of the creed of the Druids, but sanctioned by them, while they had a definite theological system with only a few gods.[1025] These are the ideas of writers who see in the Druids an occult and esoteric priesthood.  The Druids had grown up pari passu with the growth of the native religion and magic.  Where they had become more civilised, as in the south of Gaul, they may have given up many magical practices, but as a class they were addicted to magic, and must have taken part in local cults as well as in those of the greater gods.  That they were a philosophic priesthood advocating a pure religion among polytheists is a baseless theory.  Druidism was not a formal system outside Celtic religion.  It covered the whole ground of Celtic religion; in other words, it was that religion itself.

The Druids are first referred to by pseudo-Aristotle and Sotion in the second century B.C., the reference being preserved by Diogenes Laertius:  “There are among the Celtae and Galatae those called Druids and Semnotheoi."[1026] The two words may be synonymous, or they may describe two classes of priests, or, again, the Druids may have been Celtic, and the Semnotheoi Galatic (?  Galatian) priests.  Caesar’s account comes next in time.  Later writers gives the Druids a lofty place and speak vaguely of the Druidic philosophy and science.  Caesar also refers to their science, but both he and Strabo speak of their human sacrifices.  Suetonius describes their religion as cruel and savage, and Mela, who speaks of their learning, regards their human sacrifices as