Kapila, the founder of the system, whose teaching is presupposed by Buddhism, and whom Buddhistic legend connects with Kapila-vastu, the birthplace of Buddha, must have lived before the middle of the sixth century. No work of his, if he ever committed his system to writing, has been preserved. Indeed, the very existence of such a person as Kapila has been doubted, in spite of the unanimity with which Indian tradition designates a man of this name as the founder of the system. The second leading authority of the Sankhya philosophy was Panchaçikha, who may have lived about the beginning of our era. The oldest systematic manual which has been preserved is the Sankhya-karika of Içvara-krishna. As it was translated into Chinese between 557 and 583 A.D., it cannot belong to a later century than the fifth, and may be still older. This work deals very concisely and methodically with the doctrines of the Sankhya in sixty-nine stanzas (composed in the complicated Arya metre), to which three others were subsequently added. It appears to have superseded the Sutras of Panchaçikha, who is mentioned in it as the chief disseminator of the system. There are two excellent commentaries on the Sankhya-karika, the one composed about 700 A.D. by Gaudapada, and the other soon after 1100 A.D. by Vachaspati Miçra. The Sankhya Sutras, long regarded as the oldest manual of the system, and attributed to Kapila, were probably not composed till about 1400 A.D. The author of this work, which also goes by the name of Sankhya-pravachana, endeavours in vain to show that there is no difference between the doctrines of the Sankhya and of the Upanishads. He is also much influenced by the ideas of the Yoga as well as the Vedanta system. In the oldest commentary on this work, that of Aniruddha, composed about 1500 A.D., the objectiveness of the treatment is particularly useful. Much more detailed, but far less objective, is the commentary of Vijnana-bhikshu, entitled Sankhya-pravachana-bhashya, and written in the second half of the sixteenth century. The author's point of view being theistic, he effaces the characteristic features of the different systems in the endeavour to show that all the six orthodox systems contain the absolute truth in their main doctrines.