Arrived there, they began to practise those austere penances that are said by Brahman in the Vedas. Those austerest of penances are known by the name of Mahaniyama.
ते तपः समुपातिष्ठन् ब्रह्मोक्तं वेदकल्पितम्। स महानियमो नाम तपश्चर्यासु दारुणः॥