H. 5.—­From the historian Diodorus Siculus, whose life overlapped Caesar’s, we learn that Druid was a native British name.  “There are certain philosophers and theologians held in great honour whom they call Druids."[56] Whether this designation is actually of Celtic derivation is, however, uncertain.  Pliny thought it was from the Greek affected by the Druids and connected with their oak-tree worship.  Professor Rhys mentions that the earliest use of the word in extant Welsh literature is in the Book of Taliesin, under the form Derwyddon,[57] and that in Irish is to be found the cognate form Drui.  But these are as likely to be derived from the Greek [Greek:  drouides] as this from them.  Diodorus adds that they have mighty influence, and preside at all sacred rites, “as possessing special knowledge of the Gods, yea, and being of one speech [[Greek:  homophonon]] with them.”  This points to some archaic or foreign language, possibly Greek, being used in the Druidical ritual.  Their influence, he goes on to say, always makes for peace:  “Oft-times, when hosts be arrayed, and either side charging the one against the other, yea, when swords are out and spears couched for the onset, will these men rush between and stay the warriors, charming them to rest [[Greek:  katepasantes]] like so many wild beasts.”

H. 6.—­With the Druids Diodorus associates two other religiously influential classes amongst the Britons, the Bards [[Greek:  bardos]] and the Seers [[Greek:  manteis]].  The former present the familiar features of the cosmopolitan minstrel.  They sing to harps [[Greek:  organon tais lurais homoion]], both fame and disfame.  The latter seem to have corresponded with the witch-doctors of the Kaffir tribes, deriving auguries from the dying struggles of their victims (frequently human), just as the Basuto medicine-men tortured oxen to death to prognosticate the issue of the war between Great Britain and the Boers in South Africa.  Strabo, in the next generation, also mentions together these three classes, Bards, Seers [[Greek:  Ouateis] = Vates] and Druids.  The latter study natural science and ethics [[Greek:  pros te phusiologia kai ten ethiken philosophian askousin]].  They teach the immortality of the soul, and believe the Universe to be eternal, “yet, at the last, fire and water shall prevail.”

H. 7.—­Pomponius Mela, who wrote shortly before the Claudian conquest of Britain, says that the Druids profess to know the shape and size of the world, the movements of the stars, and the will of the Gods.  They teach many secrets in caves and woods, but only to the nobles of the land.  Of this esoteric instruction one doctrine alone has been permitted to leak out to the common people—­that of the immortality of the soul—­and this only because that doctrine was calculated to make them the braver in battle.  In accordance with it, food and the like was buried with the dead, for the use of the soul.  Even a man’s debts were supposed to pass with him to the shades.