The first-born son of a Leviratical marriage was registered as the son of the deceased brother. It was prevalent also among the Iranians.

The same custom came to be known as Niyoga but it changed its scope gradually.

Here we find three stages in the evolution of the custom: (1) In the first the widow is allowed to raise a son to her dead husband 74 living either with brother-in law or a man of the same caste as her husband.75 (2) In the second stage we find the custom censured76 and described as fit only for cattle.

The origin of the custom is traced to the reign of Vena-a mythical figure. Further it is said that it is not sanctioned by the Sacred Texts.77 (3) In the third stage it is not only prohibited and censured but an additional reward of heavenly bliss and good name in this world is added to a widow who will not follow it. One, who does for, the sake of off spring, will not only bring disgrace on her but also lose her place in heaven.

These widely differing views, occurring in the same context, cannot be the work of one author or of one period. The first represents the Vedic period, the second of the transitory Puranic period and the last a later period-perhaps later than that of Vishnu and Narada.