The restriction of the words Veda and Vedic to the collection of hymns, though convenient, is not in accordance with Indian usage, which applies the name to a much larger body of religious literature. What we call the Rig Veda is strictly speaking the mantras of the Rig Veda or the Rig-Veda-Saṃhitâ: besides this, there are the Brâhmaṇas or ceremonial treatises, the Âraṇyakas and Upanishads containing philosophy and speculation, the Sûtras or aphoristic rules, all comprised in the Veda or Śruti (hearing), that is the revelation heard directly by saints as opposed to Smṛiti (remembering) or tradition starting from human teachers. Modern Hindus when not influenced by the language of European scholars apply the word Veda especially to the Upanishads. For some time only three[145] Vedas were accepted. But the Epics and the Puranas know of the fourfold Veda and place the Atharva Veda on a level with the other three. It was the manual of two ancient priestly families, the Atharvans and Angirasas, whose speciality was charms and prophylactics rather than the performance of the regular sacrifices. The hymns and magic songs which it contains were probably collected subsequently to the composition of the Brâhmaṇas, but the separate poems are older and, so far as can be judged from their language, are intermediate between the Rig Veda and the Brâhmaṇas. But the substance of many of the spells must be older still, since the incantations prescribed show a remarkable similarity to old German, Russian and Lettish charms. The Atharva also contains speculative poems and, if it has not the freshness of the Rig Veda, is most valuable for the history of Indian thought and civilization.