The Tolkappiyam is

The Tolkappiyam, authored by Tolkappiyar, is the oldest surviving work of Tamil literature and serves as a comprehensive treatise on Tamil grammar and poetics. It is traditionally associated with the Second Sangam (assembly of poets) held at Kapadapuram. The text is divided into three sections (athikaram): Eluttatikaram, which deals with phonology and graphology; Collatikaram, focusing on morphology and syntax; and Porulatikaram, which discusses semantics, prosody, and the conventions of classical Tamil poetry. While it primarily functions as a grammatical work, it also provides significant insights into the social, political, and cultural life of the early Tamils during the Sangam period. It is distinct from the later didactic works like the Patinenkizkanakku or the medieval epics.