Incarnation of Goddess Ganga as river Ganga
King Sagara the ruler of Ayodhya and an ancestor of Lord Rama successfully performed the Ashwamedha Yagya (Horse sacrifice) for 99 times. Each time, he sent the horse around the Earth it returned to the kingdom unchallenged. He decided to perform the Ashvamedha Yagna for the 100th time, that would make him emperor of Earth.
When Indra (King of Gods) saw that happen, he became worried by Sagar’s increasing power. So Indra stole Sagar’s horse before the ritual could be completed and tied it to the tree under which Sage Kapila was meditating.
King Sagar’s courtiers discovered the sacrificial horse had gone missing. The king therefore ordered his 60,000 sons to go find the horse. The arrogant princes went about burning and destroying places in their quest to find the horse. And presently they came to Sage Kapila’s hermitage. They found him in meditation and the horse tied next to him. They mistook the sage to be the abductor and attacked him. Feeling disturbed and insulted, Sage Kapila burned them to ashes with yogic fire that came out of his third eye.
When Ansuman, the last remaining son of King Sagar came to know the fate of his brothers, he asked Sage Kapila how to liberate their souls from the ashes. The Rishi advised Ansuman to please Lord Brahma with penances so that he would release Ganga from his kamandula and bring Ganga to Earth to purify the ashes and liberate his brothers. But,this task was undertaken for many generations.
In the seventh generation of King Sagar, Bhagiratha was born. King Bhagirath left his kingdom and began to mediate for the salvation of the souls of his ancestors. Bhagirath observed a penance to Lord Brahma for a thousand years, requesting Ganga to come down to earth from heaven and wash over his ancestor’s ashes to release them from a curse and allow them to go to heaven. Pleased with the devotion, Lord Brahma granted Bhagirath’s wish but told him to pray to Lord Shiva, so that he would accept to hold the force of Ganga in his hairs, lest she would overwhelm the entire Earth.
Thus Bhagiratha undertook further penances to please Lord Shiva. When Ganga descended from the heavens, Lord Shiva covered the sky with his hair locks, so that not a drop would fall on Earth. When he had fully captured Ganga, Lord Shiva released a small part of Ganga’s force and told her to follow Bhagiratha. This gave Lord Shiva the name of Gangadhar, he who holds the river Ganga.
On origin Ganga flooded the ashram of Saint Janu, he swallowed her as a lesson in respect and only released Ganga out of pity for Bhagiratha. Wherever Ganga would flow in following Bhagiratha, people came in large numbers to bath and obtain purification.
Finally Ganga reached the ashram of Sage Kapila and freed the 60.000 souls from their ashes.