Mbh 9.49.1a

Vaishampayana said, "The mighty chief of the Yadus, having proceeded to Indra's tirtha, bathed there according to due rites and gave away wealth and gems unto the Brahmanas. There the chief of the celestials had performed a hundred horse sacrifices and given away enormous wealth unto Brihaspati. Indeed, through the assistance of Brahmanas conversant with the Vedas, Shakra performed all those sacrifices there, according to rites ordained (in the scriptures). Those sacrifices were such that everything in them was unstinted. Steeds of all kinds were brought there. The gifts to Brahmanas were profuse. Having duly completed those hundred sacrifices, O chief of the Bharatas, Shakra of great splendour came to be called by the name of Satakratu. That auspicious and sacred tirtha, capable of cleansing from every sin, thereupon came to be called after his name as Indra-tirtha. Having duly bathed there, Baladeva worshipped the Brahmanas with presents of excellent food and robes. He then proceeded to that auspicious and foremost of tirthas called after the name of Rama. The highly blessed Rama of Bhrigu's race, endued with great ascetic merit, repeatedly subjugated the Earth and slew all the foremost of Kshatriyas. (After achieving such feats) Rama performed in that tirtha a Vajapeya sacrifice and a hundred horse sacrifices through the assistance of his preceptor Kasyapa, that best of Munis. There, as sacrificial fee, Rama gave unto his preceptor the whole earth with her oceans. The great Rama, having duly bathed there, made presents unto the Brahmanas, O Janamejaya, and worshipped them thus. Having made diverse present consisting of diverse kinds of gems as also kine and elephants and female slaves and sheep and goats, he then retired into the woods. Having bathed in that sacred and foremost of tirthas that was the resort of gods and regenerate Rishis, Baladeva duly worshipped the ascetics there, and then proceeded to the tirtha called Yamuna.