H. 3.--The earliest testimony is that of Julius Caesar himself, in his well-known sketch of contemporary Druidism ('De Bello Gallico,' vi. 14-20). He tells us that the Druids were the ministers of religion, the sacrificial priesthood of the nation, the authorized expounders of the Divine will. All education and jurisprudence was in their hands, and their sentences of excommunication were universally enforced. The Gallic Druids were under the dominion of a Primate, who presided at the annual Chapter of the Order, and was chosen by it; a disputed election occasionally ending in an appeal to arms. As a rule, however, Druids were supposed not to shed blood, they were free from all obligation to military service, and from all taxation of every kind. These privileges enabled them to recruit their ranks--for they were not an hereditary caste--from the pick of the national youth, in spite of the severe discipline of the Druidical novitiate. So great was the mass of sacred literature required to be committed to memory that a training of twenty years was sometimes needed. All had to be learnt orally, for the matter was too sacred to be written down, though the Druids were well acquainted with writing, and used the Greek alphabet,[53] if not the Greek language,[54] for secular purposes. Caesar's own view is that this refusal to allow the inditing of their sacred books was due to two causes: first, the fear lest the secrets of the Order should thus leak out, and, secondly, the dread lest reading should weaken memory, "as, in fact, it generally does." Even so, amongst the Brahmans there are, to this day, many who can not only repeat from end to end the gigantic mass of Vedic literature, but who know by heart also with absolute accuracy the huge and complicated works of the Sanscrit grammarians.