The Jhelum River rises from a spring on the northern face of a mountain spur protruding from the Middle Himalayan Range. Flowing north through the Vale of Kashmir into Srinagar, it widens to become the Dhal Lake with its picturesque houseboats. Further north, the river enters Lake Wullar, the largest fresh water lake in the subcontinent. From the lake, the Jhelum flows into the Punjab, the land of the five rivers.

In 326 BCE, in Punjab, on opposite sides of the Jhelum, which the Ancient Greeks called the Hydaspes, the armies of Alexander and Porus faced each other. The snow in the Himalayas had melted early that year and the river was flooded posing a major obstacle to any army that wanted to cross it. Here, along the Jhelum, Porus with a smaller army fought Alexander whose army was three times larger. Despite his numerical superiority, the Battle of the Hydaspes was Alexander's most difficult battle and although the invincible Alexander won the encounter, it was a Pyrrhic victory. The determination with which the outnumbered Indians fought the Greeks, and the higher than usual casualties suffered by Alexander, demoralized his army and forced him to leave India. The Greeks, who had crossed into India through the Khyber Pass, were forced to turn back.

Porus, the Greek name for King Purushotthama, was king of the lands between the rivers Jhelum and Chenab, and belonged to the Puru tribe, an ancient clan mentioned in the Rig Veda. Bhesa in Pakistani Punjab was the historic city of the Purus. Members of the Kukhran clan, who live or originate from that area, be they Muslims, Hindus or Sikhs, among whom Prime Minister Manmohan Singh is the most notable, are thought to have descended from the Puru tribe. When Alexander's messenger informed Porus that he should proceed to Taxila (Taxiles) to meet Alexander with tribute, the defiant Porus replied that he would meet Alexander in battle if Alexander entered his realm. Porus deployed 30,000 infantry, 4,000 cavalry, 300 chariots and 200 war elephants south of the Jhelum to stop Alexander's advance.

The Greeks had met the Indians before in battle. Darius, the Persian emperor, had conquered Indian territory up to the Indus River.