Ashvagosha
Famous non-Buddhist yogi in India in Nagarjuna's time. Mentioned in Taranatha's rise of Buddhism in India {chos 'byung}. Almost defeated the monks at Nalanda in debate so they sent a message to Nagarjuna requesting help. Nagarjuna sent his disciple Aryadeva to debate with the Indian heretic. The heretic was defeated but refused to accept Buddhism so they locked him in the library. Slowly he began to read the books and one day realized that Lord Buddha's dharma was authentic. He took refuge and wrote many famous texts. [TDuff]