Amongst [the Gauls] there are generally three divisions of men especially reverenced, the Bards, the Vates, and the Druids. The Bards composed and chanted hymns; the Vates occupied themselves with the sacrifices and the study of nature; while the Druids joined to the study of nature that of moral philosophy. The belief in the justice [of the Druids] is so great that the decision both of public and private disputes is referred to them; and they have before now, by their decision, prevented armies from engaging when drawn up in battle-array against each other. All cases of murder are particularly referred to them. When there is plenty of these they imagine there will likewise be a plentiful harvest. Both these and the others1486 assert that the soul is indestructible, and likewise the world, but that sometimes fire and sometimes water have prevailed in making great changes.1487