When Alexander the Great reached the Hydaspes River in 326 B.C.E., his conquest of India came to a halt. There he was met by an Indian king named Porus, whose forces kept guard along the opposite riverbank to prevent Alexander from crossing. “The water was high at that time of year…and the current…swift and turbulent” (Arrian, 1958 Trans., p. 268), but Alexander was determined to continue, so he ordered the “continual movement of his own troops to keep Porus guessing” (Arrian, 1958 Trans., p. 267) as to where he would attempt to cross. To add to the confusion, he had his men march around making a lot of noise, which Porus would obviously respond to. But because no crossing ever accompanied the noise and marching, Porus grew complacent and stopped reacting to these movements.
Sir Aurel Stein, a British archaeologist, explored the area around the Hydaspes (Jhelum) River in the early 20th century, and did extensive research to try to determine the exact battle site, and how the terrain would have affected it. As it was fought during the “season of rains” (Stein, 1932, p. 37), he concluded that “the waters of the river, swollen by the rains and the melting snows of the mountains, rendered fording impossible” (Stein, 1932, p. 33). The flooded river was a major hindrance to Alexander’s plans, affecting where he could make a crossing, not to mention Porus’ troops were always watching the other side. Despite this, Alexander had a stroke of good fortune when his scouts came upon a crossable location. There was a “projecting spit of land, thickly wooded with different sorts of timber” and not far beyond was “an uninhabited island, also well wooded,” that would provide great cover for his army (Arrian, 1958 Trans., p. 269). Under the cover of a thunderstorm, Alexander finally had the opportunity to sneak across (Arrian, 1958 Trans., p. 271).
The terrain of the area had a big impact on where the actual fighting could take place. Due to the heavy rains the night before, “[m]uch of the ground was deep in soft mud, so [Porus] continued his advance till he found a spot where the sandy soil offered a surface sufficiently firm and level for cavalry manoeuvre” (Arrian, 1958 Trans., p. 276). “On reaching a sandy and level position [Porus] halted and drew up his troops in line of battle to await Alexander” (Hamilton, 1956, p. 27). Many historians believe that the battle that ensued, “fought in monsoon rains at the River Hydaspes…was Alexander’s military masterpiece” (Sacks, 1995, p. 17). While the initial battle actions relied heavily on cavalry, the infantry were very much needed. Luckily the battle took place on solid ground rather than mud, otherwise the horses and possibly the elephants would have been rendered useless.
Something that set the Macedonian infantry apart was their use of the sarissa, a “13- to 14-foot-long pike” (Sacks, 1995, p. 179). While not as heavily armored as Greek hoplites, “using leather or cloth” armor, as opposed to bronze, their long reach and better maneuverability helped make up for their vulnerability (Sacks, 1995, p. 179). However, Alexander’s infantry had never faced anything like Porus’ war elephants, which “plunged this way and that among the lines of infantry, dealing destruction in the solid mass of the Macedonian phalanx” (Arrian, 1958 Trans., p. 278). The infantry, “though unaccustomed to face elephants and suffering serious losses from their onslaughts, held fast” (Stein, 1932, p. 35). Under Alexander, the phalanx was mostly used to “hold [the] enemy’s charge and damage his formation, while the cavalry looked for a weak point to attack,” as was the case in this battle (Sacks, 1995, p. 179).
Toward the end of the battle, Alexander “signaled his infantry to lock shields and move up in a solid mass” to surround the Indian army (Arrian, 1958 Trans., p. 279). This move allowed Alexander to contain and cut down Porus’ remaining forces. As can be seen in the illustration below, the fighting was brutal, and, once surrounded, the Indians didn’t stand a chance against the solid Macedonian phalanx and cavalry (Castaigne (Wikipedia), 1911).
The region’s climate and terrain played a huge role in the battle, affecting troop maneuverability, as well as the actual place where the battle could be fought. In the end, Alexander’s army was able to defeat Porus, allowing him to continue his conquest of India.
Arrian. (1958). The Campaigns of Alexander (A. De Selincourt, Trans.). New York, NY: Penguin Books.
Castaigne, A. (Artist). (1911). The phalanx attacking the centre in the battle of the Hydaspes by Andre Castaigne (1898-1899) [Web Photo]. Retrieved from http://en.wikipedia.org/wiki/File:The_phalanx_attacking_the_centre_in_the_battle_of_the_Hydaspes_by_Andre_Castaigne_(1898-1899).jpg
Hamilton, J. R. (1956). The Cavalry Battle at the Hydaspes. The Journal of Hellenic Studies, 76, 26-31. Retrieved from http://www.jstor.org/stable/629551
Sacks, D. (1995). Alexander the Great; phalanx. In A Dictionary of the Ancient Greek World (pp. 14-18; pp. 178-179). New York, NY: Oxford University Press.
Stein, A. (1932). The Site of Alexander’s Passage of the Hydaspes and the Battle with Poros. The Geographical Journal, 80, 31-46. Retrieved from http://www.jstor.org/stable/1785386