Many works are attributed to him but they have not the same authenticity as the poems of Aśvaghosha. Some schools make him the author of the Prajñâ-pâramitâ but it is more usually regarded as a revelation. The commentary on it known as Mahâ-prajñâ-pâramitâ-śâstra is generally accepted as his work. A consensus of tradition makes him the author of the Mâdhyamika[212] aphorisms of which some account has been given above. It is the principal authority of its school and is provided with a commentary attributed to the author himself and with a later one by Candrakîrti.[213] There is also ascribed to him a work called the Suhrillekha or friendly letter, a compendium of Buddhist doctrines, addressed to an Indian king.[214] This work is old for it was translated into Chinese in 434 A.D. and is a homily for laymen. It says nothing of the Mâdhyamika philosophy and most of it deals with the need of good conduct and the terrors of future punishment, quite in the manner of the Hinayana. But it also commends the use of images and incense in worship, it mentions Avalokita and Amitâbha and it holds up the ideal of attaining Buddhahood. Nâgârjuna's authorship is not beyond dispute but these ideas may well represent a type of popular Buddhism slightly posterior to Aśvaghosha.[215] In most lists of patriarchs Nâgârjuna is followed by Deva, also called Âryadeva, Kâṇadeva or Nîlanetra. I-Ching mentions him among the older teachers and a commentary on his principal work, the Śataśâstra, is attributed to Vasubandhu.[216] Little is known of his special teaching but he is regarded as an important doctor and his pupil Dharmatrâta is also important if not as an author at least as a compiler, for Sanskrit collections of verses corresponding to the Pali Dhammapada are ascribed to him. Âryadeva was a native of southern India.[217] The next epoch in the history of Buddhism is marked by the names of Asanga and Vasubandhu. The interval between them and Deva produced no teacher of importance, but Kumâralabdha, the founder of the Sautrântika school and perhaps identical with Kumârata the eighteenth Patriarch of the Chinese lists, may be mentioned. Hsüan Chuang says[218] that he was carried off in captivity by a king who reigned somewhere in the east of the Pamirs and that he, Aśvaghosha, Nâgârjuna and Deva were styled the four shining suns.