Though we cannot say precisely at what date the Nāṭyaçāstra obtained definite form, we can be assured that by the time of Kālidāsa it was not merely known, but its authority was already accepted as binding on poets. The mere fact that Kālidāsa’s dramas exhibit a marvellous fidelity to the rules of the Çāstra might be explained by the theory that it drew its principles from them rather than vice versa. But in his epics Kālidāsa, in due accord with the duty of a poet to display every form of his erudition, has emphatically shown a far-reaching competence in the terminology of the Çāstra. In the Kumārasambhava [755] Çiva and Pārvatī watched the performance in honour of their nuptials of a Nāṭaka in which the different dramatic manners were combined with the junctures, the modes of the music corresponded with the sentiments, and the Apsarases displayed their grace of form. There are similar references in the Raghuvaṅça. [756] The knowledge of the Çāstra by later writers goes without saying. The author of the Mudrārākṣasa [757] depicts Rākṣasa as comparing political combinations with the work of a dramatist and giving a brief plan of the structure of the drama, and Bhavabhūti [758] and Murāri [759] alike show familiarity with the terminology of the Çāstra as well as with its rules. The most complete proof, however, of the domination of the theory is the absence of any original creations in dramatic form. There must, it is certain, have been a time when the genius of Indian poetry was active in trying and developing the new instrument of drama, but with the appearance of the Nāṭyaçāstra this creative epoch came to all intents and purposes to a close, and the writers of the classical drama accept without question the forms imposed upon them by authority, although that authority rests on no logical or psychological basis, but represents merely generalizations, often hasty, from a limited number of plays. The Nāṭaka, accordingly, remains the form of drama par excellence, a pre-eminence due to its comparative freedom from narrow restrictions as well as to the submissive spirit of the dramatists. The form serves very different purposes; it accommodates itself not only to the grace and charm of Kālidāsa, but to the unmeasured and irregular genius of Bhavabhūti; it permits of the political drama of Viçākhadatta, as well as the philosophical disquisitions of Kṛṣṇamiçra and the devotional fervour of Kavikarṇapūra’s Caitanyacandrodaya.