In every third world age (Dvapara), Vishnu, in the person of Vyasa, in order to promote the good of mankind, divides the Veda, which is properly but one, into many portions. Observing the limited perseverance, energy and application of mortals, he makes the Veda fourfold, to adapt it to their capacities; and the bodily form which he assumes, in order to effect that classification, is known by the name of Veda-vyasa. Of the different Vyasas in the present Manvantara and the branches which they have taught, you shall have an account.