The period in which the poetry of the Vedic Samhitas arose was followed by one which produced a totally different literary type--the theological treatises called Brahmanas. It is characteristic of the form of these works that they are composed in prose, and of their matter that they deal with the sacrificial ceremonial. Their main object being to explain the sacred significance of the ritual to those who are already familiar with the sacrifice, the descriptions they give of it are not exhaustive, much being stated only in outline or omitted altogether. They are ritual text-books, which, however, in no way aim at furnishing a complete survey of the sacrificial ceremonial to those who do not know it already. Their contents may be classified under the three heads of practical sacrificial directions (vidhi), explanations (arthavada), exegetical, mythological, or polemical, and theological or philosophical speculations on the nature of things (upanishad). Even those which have been preserved form quite an extensive literature by themselves; yet many others must have been lost, as appears from the numerous names of and quotations from Brahmanas unknown to us occurring in those which are extant. They reflect the spirit of an age in which all intellectual activity is concentrated on the sacrifice, describing its ceremonies, discussing its value, speculating on its origin and significance. It is only reasonable to suppose that an epoch like this, which produced no other literary monuments, lasted for a considerable time. For though the Brahmanas are on the whole uniform in character, differences of age are traceable in them. Next to the prose portions of the Yajurvedas, the Panchavimça and the Taittiriya are proved by their syntax and vocabulary to be the most archaic of the regular Brahmanas. This conclusion is confirmed by the fact that the latter is, and the former is known to have been, accented. A more recent group is formed by the Jaiminiya, the Kaushitaki, and the Aitareya Brahmanas. The first of these is probably the oldest, while the third seems, on linguistic grounds at least, to be the latest of the three. The Çatapatha Brahmana, again, is posterior to these. For it shows a distinct advance in matter; its use of the narrative tenses is later than that of the Aitareya; and its style is decidedly developed in comparison with all the above-mentioned Brahmanas. It is, indeed, accented, but in a way which differs entirely from the regular Vedic method. Latest of all are the Gopatha Brahmana of the Atharva and the short Brahmanas of the Samaveda.