A great sage whose life-story the Pandavas learnt while on pilgrimage to holy places, his wife Lopamudra was equally a great sage in her own right. Agastya is one of the saptarshis who are extolled at many places in the Vedas and a revered Vedic sage and earliest Siddhar. He is also believed to be the author of Agastya Samhita. The word is also written as Agasti and Agathiyar (Tamil: அகத்தியர் Agathiyar; Telugu: అగస్త్య; Kannada: ಅಗಸ್ತ್ಯ; Malayalam: അഗസ്ത്യ; Sanskrit: अगस्त्य; Malay: Anggasta; Thai: Akkhot). A-ga in Sanskrit means a mountain, and Asti means thrower. Agastya the Muni, son of Urvashi was born of both Gods, Mitra and Varuna. Agastya is also the Indian astronomical name of the star of Canopus, is said to be the 'cleanser of waters', since its rising coincides with the calming of the waters of the Indian Ocean. He was son of Pulasthya, son of Brahma.
Siddhar were spiritual adepts who possessed the ashta siddhis, or the eight supernatural powers. Sage Agathiyar is considered the guru of all Siddhars, and the Siddha medicine system is believed to have been handed over to him by Lord Muruga, son of the Hindu God Lord Shiva and Goddess Parvathi. Siddhars are the followers of Lord Shiva. Agathiyar is the first Siddhar. His disciples and other siddhars contributed thousands of texts on Siddhar literature, including medicine and form the propounders of the system in this world. He is considered as the Father of Tamil literature and compiled the first Tamil grammar called Agathiyam. He is regarded to have lived in 5000 years before
and specialized in language, alchemy, medicine and spirituality (yogam and gnanam). There are 96 books in the name of Agathiyar. In Tamil language the term 'Agam' means inside and 'iyar' means belong. One who belong inside (soul) is the Tamil meaning for Agathiyar.