King Mahabhishek had the honor of being invited by Indra from time to time. It so happened that at a gathering, Ganga appeared and Mahabhishek was so impressed by her that he let himself be distracted. Indra saw this as an insult to majesty and cursed the two of them to spend some time together on earth.
Mahabhishek was born as son of King Pratipa, Shantanu, and met Ganga, they married.