Swayam-vara was a pre-marriage ceremony held in a form of a tournament from which girls of noble birth could chose a husband
The story of Nala and Damayantī originates from the Mahābhārata. Damayantī was the daughter of Bhīma, King of Vidarbha and wife of Nala. Damayantī held a swayam-vara where despite the fact four deities, Indra, Agni, Varuna and Yama assumed the form of Nala, Damayantī still chose Nala and they lived happily. Kali, a personification of the Kali or iron age arrived too late for the swayam-vara and swore revenge, so determined by jealousy was Kali that he tricked Nala via gambling his lifestyle and success away, hence the banishment to the forest with Damayantī