Alexander's Invasion and the Founding of the Mauryan Empire

In 327-325 BCE, Alexander the Great, having completed his conquest of the Achaemenid Persian Empire, led his army into the northwestern Indian subcontinent, crossing the Indus in 326 BCE and defeating the local king Porus, who commanded a formidable force of war elephants, at the costly Battle of the Hydaspes. Impressed by his opponent's courage, Alexander restored Porus to power as a subordinate ally, but his own troops, exhausted after years of campaigning and unwilling to face the reportedly vast army of the Nanda kingdom of Magadha, mutinied at the Hyphasis River and forced him to abandon any further advance and begin his withdrawal.