Which emperor wrote the play 'Nagananda' in Sanskrit language?

Nagananda is among the most acclaimed Sanskrit dramas. Through five acts, it tells the popular story of Jimutavahana's self-sacrifice to save the Nagas. The unique characteristic of this drama is the invocation to lord Buddha in the Nandi verse, which is considered as one of the best examples of the dramatic compositions. Harshavardhana was the great scholar of Sanskrit and he had written this play.