When alexander set out for india in the spring of 327, it was to secure the eastern fringes of the empire – Gandhara and the Indus lands had been under Achaemenid rule since the time of Darius I, although Persian authority had weakened somewhat – not to seek the ends of the earth or greater glory beyond. As elsewhere, there were dynasts who were content to recognize the overlordship of Alexander, and even to accept Macedonian garrison troops, if it meant stealing a march on their rivals. It is therefore wrong to speak of the Macedonian conquest of India, though some enemies were clearly conquered. Instead it was a matter of restoring the authority of the empire over the eastern satrapies and establishing buffer zones. But India was a land of mystery and enchantment to the Greeks and the Romans, and it was easy to forget that Alexander had not, in fact, advanced beyond the boundaries of the Persian Empire.

The weakening of Persian authority in the Indian satrapies no doubt accounts for the fact that it was here that the Macedonians encountered the most determined resistance. In Bactria and Sogdiana, the opposition had come from the nobles who had close ties with Darius and from the local dynasts who felt secure in the mountain fortresses. But their opposition was motivated primarily by their distrust of Alexander and they were easily won over by the expedient of political marriage.