 According to Hartmut Scharfe, the oldest medicine siddhar Tamil text mentioning Agastya were composed no earlier than the 16th century.His named is spelled as "Agathiyar" or "Agasthiyar" in some Tamil texts, and some consider the writer of the medical texts to be a different person.According to Kamil Zvelebil, the sage Agastya, "Akattiyan" the Siddha, and Akatthiyar, the author of "Akattiyam", were three or possibly four different persons of different eras, who over time became fused into one single person in the Tamil tradition.