This article considers some of the connections which exist between Tamil grammar and Tamil literature. Taking as a basis the grammar composed by the Tamil scholar Cēṉāvaraiyar (13rd-14th cent.), which is a commentary on the second part of the famous ancient Tamil grammar, the /Tolkāppiyam/ (viz. the part concerning "words", i.e. syntax and morphology), the aim of this article is to delineate the literary knowledge of Cēṉāvaraiyar, and hence to determine both the corpus which he had in mind and his working methods. Cēṉāvaraiyar's commentary borrows examples both from the language spoken/written in his time (ca. 1500 items) and from classical poems (ca. 500 items evidently well-known at the time). The statistics show which parts of the poetical corpus were the most popular in the 13rd-14th cent. The high respect paid to the literary usage makes it clear that grammarians are often ready to accept "exceptions" to the (provisional) rules which they try to formulate.