King Rituparna of the solar dynasty, who ruled from Ayodhya, plays a key role in the episode of King Nala and his queen Damayanti in the Mahabharata.
Nala, who had to leave his kingdom for the forest, following the usurpation of his throne by his brother Pushkara, abandoned his queen Damayanti while she was asleep. He then went into the recesses of the forest. He happened to rescue from a forest fire Karkotaka, a big serpent. Karkotaka, however, bit Nala, as a result of which Nala became a dark dwarf. But the serpent assured the king that what he did was only for his good. It also gave him a cloth to be worn when he wanted to regain his natural form, and advised him to join King Rituparna of Ayodhya as his charioteer. Rituparna employed Nala, now called Bahuka.
Rituparna had earlier attended the first swayamvara of Princess Damayanti in Vidarbha. When the news was received that there was to be a second swayamvara the next day, he was keen on attending that also. But Vidarbha was far away from Ayodhya, and there was little possibility of reaching it. Bahuka, however, much to the surprise of Rituparna, assured him that he would take him over to Vidarbha in time (Mahabharata, Vana Parva, Chapter 67).
As the chariot was speeding its way, Rituparna’s cloak was blown off. He wanted Bahuka to stop the chariot and pick up the cloak. But Bahuka told the king that the horses, under the influence of the mantra (Ashvahridaya), had already covered quite a long distance. King Rituparna, in turn, told Bahuka tha the knew the sacred mantra of Akshahridaya (heart of numbers) which would ward off all evil spirits. Both taught each other the mantra they knew.
The two reached the palace in Vidarbha in time, where Damayanti’s swayamvar was to be held. Nala and Damayanti recognized each other and were reunited. Rituparna came to know that the announcement of the second swayamvara was only meant to find out the whereabouts of Nala. Damayanti knew that wherever he was, Nala was sure to attend the swayamvara. However, he was happy that he was instrumental in bring together the long-separated royal couple (Mahabharata, Vana Parva Chapter. 77).