No sooner was he gone than the Indians rose and slew the Greek governor; the Macedonians massacred the Indians; a new governor, sent by Alexander, murdered the friendly Punjab prince, Porus, and was himself driven out of the country by the advance of Chandragupta from the Gangetic valley.
Seleucus, after a war with Chandragupta, determined to ally himself with the new power in India rather than to oppose it.
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.).
Antiochus Theos (grandson of Seleucus Nicator) and Asoka (grandson of Chandragupta), who ruled these two monarchies in the 3rd century B.C., made a treaty with each other (256).
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.