1. Naatyasaastra, the grammar of theatre (2.c. BCE)
Bharata, in his encyclopaedic Naatyasaastra(NS), prescribes a code of conduct for playwrights and actors. He drew inspiration from his experience as an actor and also from the rich tradition he inherited. He wanted to distance himself from the populist mode of presentations prevailed at that time.  To achieve this, he took the performance from streets to the well-guarded theatre-houses, wherein admission was limited to a few hundred spectators, mostly belonging to the higher strata of the society. Secondly, he introduced a kind of stylised acting (naatyadharmi) along with the realistic (lokadharmi) mode of the popular theatre. The appreciation of naatyadharmi required high scholarship and specialised training. The connoisseur had to use his imaginative faculty and finer sensibilities to understand the performance. The third and crucial contribution of Bharata was the stress he gave to saatvikaabhinaya. This enabled him to focus on the aesthetic emotion of the spectators and to develop the wonderful theory of rasa . All the components in a performance are intended to develop the rasa.This concentration on rasa and bhaava elevated theatre to a sublime level. Spectactors were taken to a trans-temporal world, where the supreme bliss they enjoyed was akin to the supreme bliss the yogis experience.
Bharata’s theatre, later on, had its varied manifestations in different parts of the country. The broader relations between maargi and desi on the one hand and the interrelations between desis themselves marked the growth of Indian theatre in its different phases of  evolution. Kuttanimata(8 c.) contains a graphic description of the enactment of the first Act of Ratnaavali, which gives a glimpses of the improvisations on Bharata for over a thousand years. The claim of the director that this method excelled the traditional one handed down by Bharata, need not be dismissed as an exaggeration. Kashmir had close cultural relations with Kerala from ancient times . The developments in Kashmir had its immediate impact in the Southern-most tip of the peninsula. The actors of Kerala were familiar with the Kuttanimata experiment. The greatest development in Kashmir around this time was the doctrine of dhvani propounded by Anandavardhana in his Dhvanyaaloka. Ananda had to face stiff resistance in his homeland. But Kerala accepted him whole-heartedly and introduced his innovative ideas of dhvani immediately, in theatre. This was a landmark in the history of Kerala theatre.
NS had its influence in the South from very early period. Though the Vidhya mountains divided this country as Aaryaavarta in the North and Dakshinaapatha in the south, it could not prevent cross-cultural currents in these segments. Bharata himself refers to Andhras, Dramilas and other inhabitants of the South. Tolkappiyam was strongly influenced by NS.Silappadikaram provides a mine of information regarding performance traditions prevailed at that period. The thematic area of its operation extends to the whole of South India. The story spreads to three important cities of the South- Madurai, Kaverippoopattanam and Kotungalloor. It was in Kotungalloor in Kerala that the Parayur Kuttachakkiyan exhibited his unusual talent by presenting the turbulent thaandava by the right part of the body and the sober lasya by the left simultaneously, thereby playing the dance of Ardhanaareeswara. This tradition was developed after a few centuries by a royal dramatist who ruled Kerala with his capital in the same city, Mahodayapuram-the present Kotungalloor.