236 the Andhras were overthrown, and, after a confused and obscure period of about a century, Chandragupta I.
Seleucus, after a war with Chandragupta, determined to ally himself with the new power in India rather than to oppose it.
The Buddhist dynasty of Chandragupta profoundly modified the religion of northern India from the east; the Seleucid empire, with its Bactrian and later offshoots, deeply influenced the science and art of Hindustan from the west.
Later still the settlement of Brahmans along the west coast had already Aryanized the country in religion, and to some extent in language, before the Persian conquest of the Indus valley at the close of the 6th century B.C. The Persian dominion did not long survive; and the march of Alexander the Great down the Indus paved the way for Chandragupta and the Maurya, empire.
In return for five hundred elephants, he ceded the Greek settlements in the Punjab and the Kabul valley, gave his daughter to Chandragupta in marriage, and stationed an ambassador, Megasthenes, at the Gangetic court (302 B.C.).