Agastya is regarded as the father of Tamil and the compiler of the first Tamil grammar, Agattiyam.In Tamil traditions, Agastya was a culture hero and appears in numerous Tamil texts.Both traditions say that Agastya has migrated from north to south according to Iravatham Mahadevan.
The Tamil text Purananuru, dated around the beginning of the modern period, or perhaps about the 2nd century CE, mentions Agastya in verse 201 along with many people who migrate to the South.Its role in the spread of irrigation, agriculture and the Tamil language is emphasised in southern traditions.
The Tirumantiram identifies Agastya as an ascetic sage who came from the north and settled in the mountains of southern Pothigai because Shiva had asked him to.As Shiva was about to marry Parvati, the entire world visited the Himalayas. This caused the world to pounce to one side. Shiva then demanded that Agastya go to the southern area to restore the balance. So Agastya moved to the south at the behest of Shiva.
In Tamil Hindu traditions, Agastya is regarded as the first and foremost Siddhar.Together with Tirumular, Agastya is known as a siddhar in both philosophical and practical realms, unlike most other siddhars who are respected for their unique knowledge. Agastya is also famous in the Indian subcontinent for the respect he has received in historical texts.
In and after the 15th century, all medicine and health-related Tamil texts, Agastya as the Siddhar, were composed.The oldest Tamil medicine book, which mentions Agastya, was written.His named is spelled as Agathiyar in these texts.
Agastya is popular in South-East Asian Shiva temples in the mediaeval era,These temples, along with the iconography of Shiva, Uma, Nandi and Ganesha facing particular cardinal directions, include the sculpture, image or relief of Agastya carved into the south face.The Shrine of Shiva in Southeast Asia's largest Hindu temple complex, Prambanan, features four cellae within.This central shrine within the community of temples in Pramban dedicates its southern cella to Agastya.