In the Satya-yuga, the first millennium, all the Vedic mantras were included in one mantra — praṇava, the root of all Vedic mantras. In other words, the Atharva Veda alone was the source of all Vedic knowledge. The Supreme Personality of Godhead Nārāyaṇa was the only worshipable Deity; there was no recommendation for worship of the demigods. Fire was one only, and the only order of life in human society was known as haṁsa.