de bello gallico, 6.13

In all Gaul there are two classes of those men who are of any rank and dignity. For the commons is held almost in the place of slaves, and dares nothing through itself, and is admitted to no deliberation. Very many, when they are pressed either by another’s money (i.e. debt), or the magnitude of their taxes, or the injustice of the more powerful, offer themselves into slavery to the nobles, who have over them the same rights which masters have over their slaves. But of these two orders, one is that of the Druids, the other that of the knights. Those men (the former) take part in things sacred, attend to the public and the private sacrifices, and interpret religious matters: to these a great number of young men flock for the sake of instruction, and these are in great honor among them. For they decide about nearly all controversies, public and private and, if any crime has been committed, if murder has been done, if there is any dispute about an inheritance, if (any) about boundaries, these same persons decide it, they decree rewards and punishments; if any one, either in a private or public, has not submitted to their decision, they interdict him from the sacrifices. This punishment among them is the most severe. Against whom it has been thus interdicted, these are held in the number of the impious and the criminals: all withdraw from these, they flee their society and conversation, lest they receive any harm from their contact, nor is justice administered to those seeking (it), nor is any honor bestowed. One is in control over all these Druids, moreover, who has supreme authority among them. With this one having died, either, if any one from the rest excels in dignity, he succeeds; or, if there are many equal, (the election is made) by the suffrage of the Druids; not never do they even contend for the supremacy with arms. These at a certain time of the year in the territories of the Carnutes, which is considerd the middle region of the whole of Gaul, assemble in a consecrated place. Hither all from every part, who have disputes, assemble and obey the decrees and determinations of them. The discipline is thought to have been discovered in Britain and brought over thence into Gaul, and now those who wish to learn more carefully this system generally set out thither for the sake of learning (it).