Outside the Indian subcontinent, a new and far more threatening force was gathering its power. Driven out by the
Unification of China in 221 b. c., a number of nomadic tribes from Central Asia had moved westward. One of these was the Yueh-Chih (you-WAY CHEE), who arrived in Bactria in 165 b. c. The strongest of the five Yueh-Chih tribes came to be called the Kushans. Eventually they invaded the Punjab. Between about 100 b. c. and the time their greatest ruler, Kanishka (kah-NEESH-kah), took the throne in about a. d. 78, the Kushans subdued an enormous area that stretched from the Ganges deep into Central Asia.
Kanishka was a Buddhist, and by uniting such a large area of territory, he was able to spread the religion northward into China, where it came to have much greater importance than in India. This would prove to be the greatest legacy of the Kushans, who in spite of their sizeable empire declined rapidly after the time of Kanishka.
In the aftermath, the western part of the Indian subcontinent came under the domination of the Sassanians from Persia, as well as the Sakas, whose power still lingered. By then, however, a new force was arising from the west: Rome. The Romans engaged in extensive trade with India, whose wealth—in the form of jewels, ivory, spices, and other goods— was well-known in Europe.
Up to this point, the principal kingdoms of the Indian subcontinent had been based either in the Punjab and Indus Valley to the west or on the Gangetic (gan-JET-ik) Plain surrounding the Ganges to the east. But some time after 100 b. c., new kingdoms appeared on the Deccan Plateau to the south. Most important of these was the Satavahana (sah-tah-vah-HAH-nah) kingdom, which ruled the western Deccan until the a. d. 200s. There were also several important Tamil dynasties who controlled areas to the east and south.