"Amongst classical writers Caesar in the sixth book of his De bello Gallico, is the first who states that the Druids were the religious guides of the people as well as the chief expounders and guardians of the law. As, unlike the Brahmans in India, they were not an hereditary caste, and enjoyed exemption from military service as well as payment of taxes; admission to their order was eagerly sought after by the youth of Gaul. The course of training to which a novice had to submit was protracted, extending over twenty years, — resembling in this particular the system of education still in vogue in India. The office of Arch Druid was elective, extending over a lifetime, and involved supreme authority over all others. Desultory references and brief notices of the learning of the Druids are met with in the writings of Aristotle, Diogenes Laertius, the church fathers Origin, Clement of Alexandria and St. Augustine."