Manu's law, as we have seen, limits the habitations of the Aryas to the land north of the Vindhyas--from which we may conclude that this view belongs to a period when the Aryas had not yet set a firm foot on the coast of the Deccan. This extension of the Aryas to the south of the Vindhyas began, as will be seen below, after the year 600 B.C. Soon after this year we find the states on the Ganges completely arranged according to the Brahmanic law, and the prescripts of the laws of Manu; even in the first half of the sixth century we find a stricter practice in regard to marriages outside the order, and a severer asceticism than the law-book requires. The conclusion is therefore inevitable that the decisive precepts, which we find in the collection, must have been put together and written down about the year 600.[229] The introduction belongs undoubtedly to a later period. Manu is seated in solitary meditation, and there come to him the ten great saints--the book mentions Marichi, Atri, Angiras, Pulastya, Pulaha, Kratu, Daksha, Vasishtha, Bhrigu, Narada[230]--and say: "Thou alone, lord, knowest the distinction of the pure and impure castes, the true meaning of this universal order, which is self-existent; deign to explain it to us with clearness and in order." Manu then first narrates to the saints the story of creation. The highest being first created the water, and cast into it procreative seed, which became an egg, bright as gold and gleaming like the sun, and in this egg the highest being was born in the shape of Brahman. Then Brahman caused the egg to divide and formed from it the heaven and the earth and the great waters. He then divided himself into a man and a woman, and the male half (Brahman Viraj) produced him, Manu, who fashioned all things and created the ten Rishis, and the seven Manus, who in turn created animals and plants. Then the highest being caused him (Manu) to learn the book of the law by heart: he imparted it to the great saints and taught it to Bhrigu, who would recite it. Then Bhrigu takes up the word and says: "Learn from me the law as Manu has revealed it at my prayer." Bhrigu then narrates how the seven Manus had created various beings each in his age, and recites the doctrine of the four great periods of the world (p. 70), of the origin of the four castes and the majesty of the Brahmans.[231]