Recrossing the Hindu Kush, probably by Bamian and the Ghorband Valley, Alexander divides his forces.

Half the army with the baggage under Hephaestion and Perdiccas, both cavalry commanders, is sent through the Khyber Pass, while …

…Alexander himself leads the rest, together with his siege train, through the hills to the north.

His advance through Swat Cas and Gandhara is marked by the storming of the almost impregnable pinnacle of Aornos, the modern Pir-Sar, a few miles west of the Indus and north of the Buner River, an impressive feat of siegecraft.

Unable to storm the rock, Alexander seizes the hill opposite and threatens the Indians' encampment with his catapults.

They retreat but are caught, and many are slaughtered.

Alexander’s policy issue comes to a head at Opis, near Babylon, when Alexander's decision to send home Macedonian veterans under Craterus is interpreted as a move toward transferring the seat of power to Asia.

There is an open mutiny involving all but the royal bodyguard; but when Alexander dismisses his whole army and enrolls Persians instead, the opposition breaks down.

After haranguing the troops, threatening them, and finally sulking, Alexander wins back their affections; following this meretricious and emotional performance, he chooses to heal the rift symbolically by a more organized piece of theater, a great banquet of reconciliation with nine thousand guests.

Ten thousand veterans are now sent back to Macedonia with gifts, and the crisis is surmounted.

Hephaestion dies in Ecbatana in autumn 324 BCE, and …

…Alexander indulges in extravagant mourning for his closest friend; he is given a royal funeral in Babylon with a monstrous funeral pyre (never completed) costing ten thousand talents.

His post of chiliarch (grand vizier) is left unfilled.

It is probably in connection with a general order now sent out to the Greeks to honor Hephaestion as a hero that Alexander links the demand that he himself should be accorded divine honors.

For a long time his mind has dwelt on ideas of godhead.

Greek thought draws no very decided line of demarcation between god and man, for legend offers more than one example of men who, by their achievements, acquired divine status.

Having on several occasions encouraged favorable comparison of his own accomplishments with those of Dionysus or Heracles, Alexander now seems to have become convinced of the reality of his own divinity and to require its acceptance by others.

There is no reason to assume that his demand has any political background (divine status gives its possessor no particular rights in a Greek city); it is rather a symptom of growing megalomania and emotional instability.

The cities comply, but often ironically: the Spartan decree reads, “Since Alexander wishes to be a god, let him be a god.”

Alexander is by spring 324 BCE back in Susa, capital of Elam and administrative center of the Persian Empire (the story of his journey through Carmania in a week-long drunken revel, dressed as Dionysus, is embroidered, if not wholly apocryphal.)

He finds that his treasurer, Harpalus, evidently fearing punishment for peculation, has absconded with six thousand mercenaries and five thousand talents to Greece.

Alexander holds a feast to celebrate the seizure of the Persian Empire, at which, in furtherance of his policy of fusing Macedonians and Persians into one master race, he and eighty of his officers take Persian wives; he and Hephaestion marry Darius' daughters Barsine (also called Stateira) and Drypetis, respectively, and ten thousand of his soldiers with native wives are given generous dowries.

Alexander also marries Parysatis, the daughter of Artaxerxes III.

Ptolemy, whom Alexander has decorated several times for his deeds, is in the ceremony married to the Persian Artacama.

Seleucus marries Apama, the daughter of Spitamenes, the ruler of Bactria.

This policy of racial fusion brings increasing friction to Alexander's relations with his Macedonians, who have no sympathy for his changed concept of the empire.

His determination to incorporate Persians on equal terms in the army and the administration of the provinces is bitterly resented.

This discontent is now fanned by the arrival of thirty thousand native youths who have received a Macedonian military training and by the introduction of Orientals from Bactria, Sogdiana, Arachosia, and other parts of the empire into the Companion cavalry; whether Orientals had previously served with the Companions is uncertain, but if so they must have formed separate squadrons.

In addition, Persian nobles have been accepted into the royal cavalry bodyguard.

Peucestas, the new governor of Persis, gives this policy full support to flatter Alexander; but most Macedonians see it as a threat to their own privileged position.