In the days of As'oka the Parthians revolted against Antiochus, and, under the family of the Arsacidae, carved out for themselves a small kingdom to the north of the Seleucid Empire. They were by origin Sacae or Scythians, and their earlier home had been in the plain country between the Caspian Sea and the Oxus. Their religion was that of Zoroaster, or rather, perhaps, that of the Magi. What the precise tenets of that religion were, it is hard to say; they do not seem to have been precisely those of the Persians before the fall of the Persian Empire, nor yet those of the restored Zoroastrianism of the Sassanid period. They probably worshipped the heavenly bodies, paid a great deal of attention to astrology and astronomy, and in other points were not very unlike the Buddhists in their belief and practices. That Buddhism obtained some hold among them is shown by the fact that Parthian missionaries in later days took part in the evangelization of China; but when that influence began it is impossible to say. At a much later date, when the Buddhist evangelization of China was well established, we find Zoroastrian monks treated as brethren, and we read of Buddhists in Persia presenting a Chinese Emperor with a tooth-relic of the Buddha. And in the Shiite and Sufite forms of Mahometanism we may, it is said, see the ancient Buddhism of Persia still asserting itself.

Next to Parthia came Bactria, the reputed home of Zoroaster himself. Bactria asserted its independence in the same year as Parthia. It had Greek kings, and a small percentage of Greek settlers, the residue of the Macedonian invasion; but its main population was probably of S'akyan origin. Indian writers speak of the Bactrian people as Vrijji, the same name that we found amongst the Nepaulese S'akyans of S'akyamuni's time, and recognized them as being Kshatriyans by caste, though their standing was defective by reason of intermarriages with other nationalities. Their religion was a mixed one, Parthian, Brahmanic, Buddhist, with probably a slight preference for the last.

Bactria marches on the Pamirs. East of the Pamirs, and north of what is now Thibet, dwelt the S'akyas, separated from the S'akyan brethren of India and Nepaul by the common pasture lands of Thibet. When they afterwards emerged from their mountain fastnesses they were divided into four tribes, Asii, Pasiani, Tokhari, and Sakarauli (Strabo, ix. 8), and it is recorded (Kern, "Buddhismus," ii. 272) of the Northern Patriarch Dhitika that he made conversions by his labours among the Tokhari, who eventually gave their name to the whole of that tribe of S'akyans. As'oka's envoys did not reach these tribes, but there were many traders who carried the faith.

East of the S'akyans, in the valley of the Tarim, lay the Uighurs, the most civilized and literary of all the Scythian tribes; beyond them, to the south of Lake Lob,