AncientBattles.com_Hydaspes

"However, at last [King Porus] preferred to march against Alexander himself with all his army, and to come into a decisive conflict with the strongest division of the Macedonians, commanded by the king in person. But nevertheless he left a few of the elephants together with a small army there at the camp to frighten the cavalry under Craterus from the bank of the river. He then took all his cavalry to the number of 4,000 men, all his chariots to the number of 300, with 200 of his elephants and 30,000 choice infantry, and marched against Alexander. When he found a place where he saw there was no clay, but that on account of the sand the ground was all level and hard, and thus fit for the advance and retreat, of horses, he there drew up his army. First he placed the elephants in the front, each animal being not less than a plethrum[1] apart, so that they might be extended in the front before the whole of the phalanx of infantry, and produce terror everywhere among Alexander's cavalry. Besides he thought that none of the enemy would have the audacity to push themselves into the spaces between the elephants, the cavalry being deterred by the fright of their horses; and still less would the infantry do so, it being likely they would be kept off in front by the heavy-armed soldiers falling upon them, and trampled down by the elephants wheeling round against them. Near these he had posted the infantry, not occupying a line on a level with the beasts, but in a second line behind them, only so far distant that the companies of foot might be pushed forward a short distance into the spaces between them. He had also bodies of infantry standing beyond the elephants on the wings; and on both sides of the infantry he had posted the cavalry, in front of which were placed the chariots on both wings of his army.."

The Anabasis of Alexander by Arrian, translated by E. J. Chinnock Book V

https://en.wikisource.org/wiki/The_Anabasis_of_Alexander/Book_V/Chapter_XV

Alexander's last battle The Hydaspes River 326 BC

Alexander's last battle
The Hydaspes River 326 BC