The Battle of the Hydaspes also known as Battle of Jhelum, or First Battle of Jhelum, was fought between Alexander the Great and Porus in May of 326 BC. It took place on the banks of the Hydaspes River in Punjab, as part of Alexander's Indian campaign. In what was possibly their most costly engagement, the Macedonian army secured a decisive victory over the Pauravas and captured Porus. Large areas of Punjab were subsequently absorbed into the Macedonian Empire; Porus was reinstated as the region's ruler after Alexander, having developed a newfound respect for the fierce resistance put up by Porus and his army, appointed him as a satrap.

Alexander III of Macedon, most commonly known as Alexander the Great, was a king of the ancient Greek kingdom of Macedon. He succeeded his father Philip II to the throne in 336 BC at the age of 20 and spent most of his ruling years conducting a lengthy military campaign throughout Western Asia, Central Asia, parts of South Asia, and Egypt. By the age of 30, he had created one of the largest empires in history, stretching from Greece to northwestern India. He was undefeated in battle and is widely considered to be one of history's greatest and most successful military commanders.