Mezhathol Agnihothri (born 342 AD) revived the traditions of the ancient Shrauta traditions in Kerala, India the 4th century AD. At that time, Buddhism and Jainism had eroded the ancient Vedic Religion culture of India. Mezhathol rejuvenated the ancient customs by performing 99 Yaagams. The Shrauta traditions still remain intact in Kerala today, maintained by the rigidly orthodox Nambudiri Brahmins.
Mezhathol was the first child of the famous Parayi petta panthirukulam (12 children born from the Pariah woman), as the son of Vararuchi. He is said to have been born in 342 AD, and was found on the banks of the Nila River by an Antharjanam belonging to the Vemancheri Mana
Mezhathol Agnihothri began gathering interest in the Yaagam culture and proceeded to perform 99 Yaagams, one after the other. However only seven of the original 32 Nambudiri Graamams (Villages) agreed to assist Mezhathol, and today only these Graamams (Taliparamba, Alathur, Karikkad, Panniyur, Sukapuram, Perumanam and Irinjalakkuda) have the right to perform Yaagam. 17 Nambudiri experts are required to perform Yaagam, and they come from Kalakandathur Griham, Maathur Griham, Kulukkamillaavur Griham, Chemmangad Griham, Pazhoor Griham, Muringoth Griham and Vella Griham.
It is believed that if a person performs 100 Yaagams, that person has the same status of Indran. After Mezhathol performed 99 Yaagams, Indran, worried that he may lose his power, requested Mezhathol not to perform the 100th Yaagam. Mezhathol declined, explaining that he was not performing the Yaagams for personal gain, but to retain the culture of Yaagam amongst Brahmins. At this, Indran gave Mezhathol and his seven associates the same status as himself.
The assistance of 8 Nambudiri families (Griham) was recognised by Mezhathol Agnihotri and he classed these 8 families as the Ashtagrihathil Aadhyanmaar (Eight Elite Families). Members of these families are known as ''Aadhyan'' Nambudiris ("Aadhyan" literally means "the first one" in Malayalam). Adhyans adopted the title of "Nambudiripad" to show their superior status. However in the subsequent centuries, several non-Aadyan families (known as Aasyan Nambudiris) have also adopted the title of "Nambudiripad" in imitation of Adhyan Nambudiris.
It is believed that Agnihothri wrote the books "Bhaavanaavivekam", "Sphotasidhi", "Brahmasidhi", etc. using the pen name "Mandanamisra" and three poems in Chenthamizhu included in "Purananoor" in the pen name of "Vanparanar". The famous scholars Payyur Bhattathiris claim their ancestry to Agnihothri.