The campaign in the Punjab saw Alexander, supported by his Indian ally Taxiles, attack Porus, who lived beyond the Hydaspes River. The battle, at the beginning of the monsoon season, involved a division of the Macedonian forces. One part faced Porus at the river crossing, where the current and the elephants in the Indian army made a direct attack virtually impossible. Alexander took a portion of his army and marched upstream. Once across the river, he drew Porus away from his defensive position and defeated the Indian ruler in a battle fought primarily by cavalry, although the Macedonian pikemen inflicted injuries on the elephants, which became a danger to their own troops. After the Hydaspes victory, Alexander advanced to the Hyphasis (Beas), where the army refused to cross in order to march to the Ganges. The whole episode was contrived, since Alexander clearly had no intention of going farther east. His failure to reach the eastern end of the world was thus attributed to the timidity and war-weariness of his soldiers. During the descent of the Indus river system, Alexander received a near-fatal wound at the hands of the Mallians. Once he recovered, Alexander conducted a series of bloody massacres as he sailed to the mouth of the Indus and accomplished his goal of sailing out into the ocean. Although the Indian campaign was by far the bloodiest of the expedition, there was little long-term gain from the conquest.
Downstream and seasonal changes of lithium isotope ratios in the Ganges‐Brahmaputra river system
