[1][2] Alexander was defining the eastern limit of his power by marching down-river along the Hydaspes to the Acesines (now the Jhelum and Chenab), but the Malli and the Oxydraci combined to refuse passage through their territory.

Alexander sought to prevent their forces meeting, and made a swift campaign against them which successfully pacified the region between the two rivers.

At this time, his conquests stretched from Greece into India; some of the Indian tribes had previously been part of the Persian Empire.

[5] Alexander had defeated King Porus at the Battle of the Hydaspes in May 326 BC, and then stayed in his territory for thirty days.

[6] Abisares of Kashimir submitted to the Macedonians as well, and gave them many gifts, including forty elephants.

[6] Alexander proposed to march further east to the River Ganges and fight the powerful empires of the Nanda and the Gangaridai.

According to the second century Greek historian Arrian, he expressed his thoughts thus: Now if anyone desires to hear where our warfare will find its end and limit, let him know that the distance from where we are to the river Ganges is no longer great; and this you will find is connected to the Hyrcanian sea; for the great sea surrounds the entire earth.

Coenus' spoke on behalf of the troops and pleaded with Alexander to allow them to return, to the agreement of the other officers.

[7] After uniting with Memnon's forces, Alexander decided to head south, following the river Hydaspes, after the omens ostensibly declared it unfavourable to march further east.

Initially, the fleet and army just sailed down the river, occasionally marching short distances inland.

[10] Alexander received news that the Mallians and the Oxydracians had decided to trade hostages with each other, and moved all their valuables into their fortified cities.

After the Battle of Gaugamela Alexander and his forces are alleged to have reached the Great Zab, 34 miles (55 km) from the battlefield, only one day later.

[14][page needed] The Hydaspes and Acesines were dangerous to sail down in this area, and the Macedonians sustained considerable damage to some of their ships, in addition to some casualties.

[15][16] The Macedonians destroyed their capital city and burned their crops, slew all the males, and enslaved the women and children.

Alexander was determined not to let the Mallians escape him, and therefore he planned a sophisticated campaign that allowed him to retain the interior lines, so that he could reinforce himself at any threatened point.

[17] He added Philip's corps, Polyperchon's brigade, the horse-bowmen and the elephants which had been marching down the river, to Craterus' force.

[18] He then ordered Nearchus to sail down the river with the fleet and establish a base to conduct further operations at the junction of the Acesines and the Hydraotis.

[17] After starting across the desert, Alexander marched continuously, with only a single half-day halt at a place where water could be obtained.

[23] This is another example of Alexander taking up each and every task he deemed to be important in person, this was a practice he repeated throughout all of his campaigns.

[24] The torsion catapult was the most powerful of the era, and had revolutionised siege warfare; Alexander would use it to capture all the other cities in the region.

[23] When Perdiccas arrived at the town he was supposed to take, he found it empty; he chased down the survivors and put them to the sword.

[citation needed] Before continuing his campaign against the Mallians, Alexander sent Peithon and Demetrius back towards the river, the forests, and the desert.

[30][clarification needed] The Malli offered battle to Alexander on the high ground of the western bank of the Hydraotis.

[citation needed] When the Macedonians reached Alexander, "who was lying in a faint condition",[39] some of them placed him on a shield and quickly ran back with him to a tent.

According to Arrian, some authors "stated that Critodemus, a physician of Cos, an Asclepiad by birth, made an incision into the injured part and drew the weapon out of the wound",[41] while others claimed "that as there was no physician present at the critical moment, Perdiccas [...] at Alexander's bidding",[39] removed the arrow with his sword, causing "a copious effusion of blood"[39] which rendered Alexander unconscious.

The soldiers were very anxious about his health, since they believed he was the only one who could lead them "back in safety to their own country, being quite enclosed by so many warlike nations, some of whom had not yet submitted, and who they conjectured would fight stoutly for their freedom; while others would no doubt revolt as soon as they were relieved of their fear of Alexander.

[42] He was eventually placed upon a boat so that he and his men could see one another, with Alexander ordering "the tent covering to be removed from the stern, that he might be visible to all.

"[43] In spite of this, his troops were initially still under the impression that he was dead, and that "his corpse was being conveyed on the vessel",[43] until "he stretched out his hand to the multitude".

[43] However, his health was in such a delicate state that during his course down the river they would not even row the boat, for fear that the oars slapping the water would disturb him.