Sagara (Vedic king)
King Sagara is one of the greatest kings of the Suryavansha in the Satya Yuga, also known as the Ikshvaku dynasty, he has two wives, one a princess of the Vidarbha, and the other from royal lineage of Sivi  He was an ancestor to King Dasharatha and Lord Rama (Incarnation of Sree Vishnu).
Birth of Ganga
King Sagara performed a horse sacrifice (Ashwamedha yajna) to prove his supremacy. Lord Indra, the leader of the demigods, became fearful over the results of the yajna, so he decided to steal the horse. He left the horse at the ashram of Kapila, who was in deep meditation. King Sagar’s 60,000 sons, (born of Queen Sumati), and his son Asamanja (born of Queen Keshini) were then sent to find the horse. When the 60,000 sons found the horse at Kapiladeva’s ashram, they thought he had stolen it. When they prepared to attack the meditating rishi (sage), Kapila opened his eyes. Because the sons of King Sagara had disrespected such a great personality, consequently, fire emanated from their own bodies, and they were immediately burned to ashes.
Later, King Sagara sent his grandson Amshuman to retrieve the horse. Kapiladeva returned the horse and told Anshuman that the sons of King Sagar could be delivered if the Ganges descended to earth and bathed them in her waters. King Sagar’s great-great-grandson, Bhagiratha, eventually pleased Mother Ganga, and asked her to come to earth. Mother Ganga told Bhagiratha that the force of the Ganges falling from heaven would be too great for the earth to sustain, and that she needed someone to break the fall. Bhagiratha then worshiped Lord Siva, who then agreed to accept the descending river upon his head. After the Ganga fell down on the ashes of the 60,000 sons of King Sagara they came alive and got their eternal position.
- Ikshaku tribe The Mahabharata translated by Kisari Mohan Ganguli (1883 -1896), Book 3: Vana Parva: Tirtha-yatra Parva: Section CVI, p. 228 'There was born in the family of the Ikshaku tribe, a ruler of the earth named Sagara, endued with beauty, and strength...".
- Sons of Sagara Vishnu Purana translated by Horace Hayman Wilson, 1840, Book IV, Chapter IV. p. 378 the gods repaired to the Muni Kapila, who was a portion of Vishńu, free from fault, and endowed with all true wisdom. Having approached him with respect, they said, "O lord, what will become of the world, if these sons of Sagara are permitted to go on in the evil ways which they have learned from Asamanja! Do thou, then, assume a visible form, for the protection of the afflicted universe." "Be satisfied," replied the sage, "in a brief time the sons of Sagara shall be all destroyed."