Sagara's Lineage Continues Through Anshuman and Dilipa
After completing the sacrifice, Sagara is honored by the gods and hands the kingdom to his grandson Anshuman before departing to heaven. Anshuman rules well, then passes the throne to his son Dilipa — who, grieving for his dead ancestors, tries desperately to bring down the Ganga but fails, and eventually hands the burden to his son Bhagiratha before retiring to the forest.
When the sacrifice was complete, the gods honored Sagara. He thought of the ocean — Varuna's abode — as his son, and ruled the kingdom for a long time. Then he handed the burden to his grandson Anshuman and went to heaven.
Anshuman ruled the earth as his grandfather had, up to the frontiers of the ocean, with dharma in his soul. When his time came, he passed the kingdom to his son Dilipa and left.
But Dilipa had heard the story of his fathers — the sixty thousand sons of Sagara, burned to ashes in the depths of the earth, still un-purified. The grief of it overwhelmed him. He thought constantly about their end. He made great efforts to bring down the Ganga from heaven, because Kapila had said that only the descent of the celestial river could purify the ashes of Sagara's sons.
He tried with all his strength. He could not do it.
Dilipa had a son named Bhagiratha — truthful, devoted to dharma, a man of whom no one spoke ill. Dilipa instated Bhagiratha in the kingdom. Then he resorted to the forest, leaving the task to his son. There, through austerities, he obtained success, and in due course of time, he went to heaven.
The burden passed to Bhagiratha. Aranyaka Parva, Chapter 403