In addition to these private sacrifices, they had also similar human sacrifices of a public character.

Caesar further contrasts the Germans with the Gauls, saying that the former had no Druids to preside over matters of religion, and that they paid no attention to sacrifices.
In his work on divination, Cicero, too, refers to the profession which the Druids made of natural science, and of the power of foretelling the future, and instances the case of the AEduan Diviciacus, his brother's guest and friend.

Nothing is here said by Cicero of the three classes implied in Diodorus, but Timagenes (quoted in Ammianus) refers to the three classes under the names 'bardi,' 'euhages' (a mistake for 'vates'), and 'drasidae' (a mistake for 'druidae').

The study of nature and of the heavens is here attributed to the second class of seers (vates).

The highest class, that of the Druids, were, he says, in accordance with the rule of Pythagoras, closely linked together in confraternities, and by acquiring a certain loftiness of mind from their investigations into things that were hidden and exalted, they despised human affairs and declared the soul immortal.