Ratnavali is a Sanskrit drama about a beautiful princess named Ratnavali, and a great king named Udayana. It is attributed to the Indian emperor Harsha (606-648). It is a Natika in four acts. One of the first textual references to the celebration of Holi, the festival of Colours have been found in this text.
The astute minister Yougandharayana plans Udayana's marriage with Ratnavali, the daughter of Vikramabahu. This plan is motivated by a sage's prediction that the person who would marry her would become a Sarvabhauma (emperor). But Udayana is already married to Vasavadatta, who happens to be Vikramabahu's niece. Naturally, Vikramabahu rejects Yougandharayana's plan for fear of wounding Vasavadatta's feelings.
Yougandharayana then spreads a rumour that Vasavadatta has died in a fire at Lavanaka. After hearing this, Vikramabahu agrees to the marriage of Ratnavali to Udayana. The marriage takes place with great pomp, but because of a custom, the bride and groom do not see each other's face clearly during the marriage, and can only see each other after some traditional rites after they reach Kaushambi. Ergo, after the marriage, the couple are escorted back to Kaushambi in a ship. Unfortunately, the ship wrecked on the way. Udayana is rescued and is taken back to Kaushambi. Ratnavali is also rescued, but in a separate path, by a merchant and brought to Kaushambi. Yougandharayana comes to know of her rescue, puts her in Vasavadatta's custody renaming her as Sagarika, without disclosing her identity as the princess.
Once, in the cupid festival, Sagarika sees Udayana, but does not recognize him as her husband. She is wonder-struck by his beauty, and instantly falls in love with him. Sagarika sits in a grove and keeps herself occupied in drawing Udayana's picture and fantasizing about him. Her shrewd friend Susangatha finds her, takes the picture into her hands and draws the picture of Sagarika by the side of the king. Sagarika confesses her love to Susangatha and a bird Sarika hears the conversation. Suddenly, there is a panic in the grove because of an escaped monkey and the maidens run away from there.
After a while, the Udayana and his jester enter the grove and hear the bird Sarika reproduce the ladies' conversation. They find the picture Sagarika and Susangatha have drawn, and Udayana finds it alluring. By this time, the two maidens return and overhear the conversation of the king and his jester, and see that Udayana is interested in Sagarika. Susangatha then makes a plan to bring Udayana and Sagarika together, but Vasavadatta (Udayana's first wife) also finds the picture when walking in the grove. Susangatha's plan is destroyed by the angry Vasavadatta and she leaves the grove without accepting Udayana's words of appeasement.
In the third act, the jester and Susangata hatch a plan to make Udayana and Sagarika meet. Sagarika disguises herself as Vasavadatta, and Susangata as her maid. They go to meet Udayana, who has been told of the plan and is expecting Sagarika to come in Vasavadatta's disguise. But the real Vasavadatta comes to know of this plan and also sets off to meet Udayana. Vasavadatta reaches him first, but Udayana mistakes her for Sagarika and declares that he loves her. Vasavadatta is very angry at Udayana for the second time, and reproaches him and walks away. Sagarika comes to know that their plan is foiled again, and ties a noose to her neck wanting to commit suicide. Meanwhile, Udayana is frantically searching for the real Vasavadatta, and finds Sagarika about to die. He mistakes her for the real Vasavadatta, and saves her. Afterwards, the two recognize each other and finally they have a chance to declare their love. But at exactly the same moment, Vasavadatta, having calmed down, comes back to Udayana ready for appeasement. She is outraged for the third time on seeing Sagarika and Udayana together, and throws Sagarika into prison.
In the fourth act, no one knows where Sagarika is imprisoned by Vasavadatta. Suddenly, there is heard a news of the royal harem catching fire. It turns out that Sagarika is kept there, and Vasavadatta turns remorseful. She implores Udayana to run to her rescue. Udayana comes out safely from the fire with Sagarika. It is later revealed that the entire fire was a trick by a magician. At this tense moment, Babhravya and Vasubhuti recognize Sagarika to be the Simhala princess. Yaugandharayana enters and reveals himself to be the plotter. Vasavadatta now gladly brings about the marriage of Udayana and Ratnavali, her cousin, relying on the prophecy.
A Natika should be based on an invented love-story according to Sahityadarpana. But this play, although a natika, does not present to us an entirely original story.
The Udayana legend is found in both Jaina and Bauddha literature besides the Kathasaritsagara, Brihatkathamanjari and Brihatkathalokasangraha. The Jaina legends are not earlier than the 12th century, while the Bauddha ones are of about 4th century.
Many distinguished poets of ancient India, who flourished evn before Sri Harsha, have referred to the love of Udayana and Vasavadatta, and the devotion of Yougandharayana for his master Udayana. This shows how popular the story of Udayana was even in Ancient India. Kalidasa has referred to Udayana in his Meghaduta. Śudraka refers in his Mricchakatika to the devotion of minister Yaugandharayana to Udayana. Bhāsa has dramatized the story in his two plays Pratignayougandharayanam and Swapnavāsadattam.
In conclusion, it can be said that it is not unlikely that Sri Harsha took the frame-work of the Udayana story from either the Bauddha literature or some early version of the Brihatkatha and dramatized it in his own way. Although the story is not entirely invented, it must be admitted that the treatment of it at Harsha's hands is quite original and that the play on the whole is a very charming one.