The daughter of Vaivaswatamanu.

Antecedents: Vishnu – Brahma – Marichi – Kashyapa – Vaivaswatamanu – Ila.

Vaivaswatamanu was born to Kashyapa and Aditi, and Ila was born to him and Shradha. Ila’s brother was Ikshvaku, the forefather of the Suryavanshi kings. Manu and Shradha remained childless for a long time. Once Manu got Vasishta to do a yajna to appease Mitra and Varuna for a son. The head priest was Agastya. Soon a daughter was born to him and this was Ila. Manu asked Vasishta why a girl was born when he had wanted a boy. Vasishta immediately used his energy to change the girl into a  boy and named him Sudyumna.

Once, after Sudyumna had grown up, he went into the forests for a hunt. Near Kailash, there is a forest named Kumaravana. Once Shiva and Parvati were copulating there. Without knowing that, Shunaka and other sages decided to pay them a visit. They came across the naked pair, who weren’t pleased by the intrusion. Parvati decreed that whoever entered the forest henceforth would become a woman. Sudyumna didn’t know this and entered the forest with his friends. They all became women, and were disappointed. After staying there for a few days, they decided to return.

Sudyumna had become a beautiful woman named Ila. On her way back she met Budha. They fell in love and got married. Their son was Pururavas, as per Bhagavata. But Ila was not happy about her form and made her grief known to Vasishta. Vasishta prayed to Shiva for Ila to get her previous form back. Shiva blessed that Ila would spend alternate months as male and female for the rest of her life. As a male, he would rule over the kingdom and would then retire for a month in her female form. As per the Brahmandapurana Chapter 32, Ikshvaku ruled as regent until Pururavas came of age. As soon as Pururavas took over the running of the kingdom, Sudyumna went off to the forests to meditate. There he learned the Navakshara mantra from Narada, and with this, prayed to Devi. As per the Bhagavata, Devi appeared and gave him moksha. Pururavas married Urvashi as per Bhagavata Navamaskanda, Devibhagavata Prathamaskanda, Mahabharata Adiparva Chapter 75, and Anushasanaparva Chapter 147 verse 26.