The Battle of the Hydaspes

The conquest of Persepolis marked the final triumph of the Greco-Macedonian army over the Achaemenid Empire, but Alexander's campaign deep into Asia was far from over. Driven by immense ambition, the Macedonian king led his army further east, establishing his rule over the vast territories of Parthia, Central Asia, and India. On the edge of the known world to the Greeks, Alexander faced fierce resistance, and on the banks of the Hydaspes, the Macedonians first experienced the power of war elephants. This article narrates Alexander's most challenging military campaigns—his operations in Bactria and India, culminating in his last major battle: the Battle of the Hydaspes in 326 BC.

Alexander the Great (356-23 BC) and Porus

Background of The Battle

The year 329 marked Alexander’s conquest of Bactria. At first, the local population did not resist the Macedonian king: Alexander easily captured the largest Bactrian cities and stationed garrisons there. The local aristocrats even sought to ingratiate themselves with Alexander: they captured Bessus and left him by the road, naked, in chains, and with a dog collar. Sources differ regarding Bessus' fate: he either died on the spot, was hanged where Darius III had died, or was sent to Ecbatana and beheaded.

In any case, his death served as a lesson: such a fate awaited anyone who dared to challenge Alexander. However, Bessus' surrender did not stop Alexander, and he led his army further into Sogdiana. The local population initially hoped to secure broad autonomy within Alexander’s empire, but soon realized the futility of their hopes. Skirmishes between the Macedonians and the Sogdians broke out frequently, although the major cities, such as Bactria, surrendered without resistance.

Realizing the fragility of his rule in Sogdiana, Alexander decided to establish a new city on the northeastern edge of his kingdom, which was named Alexandria Eschate—Alexandria the Farthest. There, he settled Greek mercenaries who were unfit for Macedonian service, along with local Sogdians.

At this time, a full-scale rebellion of the Bactrians and Sogdians broke out in Alexander's rear, further complicated by the activity of the Sacae—a nomadic Scythian people living in Central Asia at that time. In response, Alexander employed harsh military tactics and bathed Bactria and Sogdiana in blood. The locals retaliated by massacring Macedonian garrisons in the conquered cities and launching daring attacks on Macedonian detachments.

Nicolas-André Monsiau, ''Alexander the Great Attacking the Oxydrakai'', 1809

In one such skirmish, which took place on the River Polymethus, the Sogdian noble Spitamenes, with the help of the Scythians, managed to defeat a Macedonian corps of four thousand men decisively. This was the first significant defeat for the Macedonians in the entire seven-year campaign, and Alexander, seeking to preserve his reputation as an invincible commander, threatened death to any survivors who spoke of the battle. However, Spitamenes could not capitalize on his victory and was soon killed by the Scythians, who feared Alexander’s retaliation.

A significant problem for the Macedonians was also the mountain fortresses, which served as strongholds for the rebels. One of these fortresses, known as the "Sogdian Rock", was situated on a cliff and seemed so impregnable that when Alexander offered the Sogdians to surrender, they merely laughed at him, suggesting he look for soldiers with wings to capture their stronghold. To assault the rock, Alexander sent three hundred men when who were experienced in climbing. They equipped themselves with iron spikes and ropes and began their ascent up the sheer wall at night. Clinging to crevices in the rock or cutting into ice, the Macedonians hauled each other up. After losing thirty men, the climbers reached the summit at dawn, and the astonished Sogdians immediately surrendered.

However, despite Alexander's military successes, his final reconciliation with the local aristocracy came only with his marriage to Roxana, the daughter of a local noble. Hostilities in Bactria finally ceased, and in 327 BC, Alexander was able to turn his attention to the last unconquered part of the Achaemenid Empire—the Persian territories in India.

Crossing the Hindu Kush for the second time, the Macedonian army fought its way through the lands of the Aspasians and Assakenes, and after a difficult crossing of the Indus River, reached the territory of the Indian king Taxiles. The real name of this rajah was Ambhi, but the Macedonians had only a vague understanding of India and confused the king's name with the name of the city where he ruled.

Taxiles gave Alexander and his army a warm reception, which, however, was not without political motivations. At that time, Taxiles was being heavily pressured by his regional rivals, particularly King Porus, who ruled on the other side of the Hydaspes. Porus was not willing to become Alexander's subject and confronted him with an army. A clash between the two leaders became inevitable.

Disposition of the Troops

Por decided to engage the Macedonians in battle on the border of his lands at the Hydaspes River. It was mid-summer of 326 BC, and the Hydaspes was a powerful stream, difficult to ford. Moreover, Por had blocked all the river crossings with his large army, and his war elephants instilled fear in Alexander's soldiers.

It is quite difficult to determine the exact size of the army commanded by Por. It is believed that he brought about 30,000 infantry, up to 4,000 cavalry, a hundred elephants, and around 500 light chariots to the Hydaspes.

The size of the Macedonian army is estimated at 30,000 infantry and 10,000 cavalry. In the open field, Alexander would have easily defeated Por's army, but this time a wide river separated the opponents, and Alexander would need to show considerable ingenuity to overcome the Indians opposing him.

Immediately after setting up camp, Alexander began sending his cavalry along the river. The Indians mirrored the movements of the Macedonian patrols to prevent a surprise crossing. Each time the Macedonians seemed to find a favorable crossing point, Por would block it with substantial force. These maneuvers continued for several weeks and greatly exhausted the Indians. Moreover, the Macedonians never actually attempted to cross, causing Por’s vigilance to noticeably dull. This was the moment Alexander had been waiting for. On his orders, Macedonian craftsmen prepared a fleet of rafts and small 30-oared galleys, positioning them upstream on the Hydaspes, where they were hidden from Por’s observers.

The Battle of Hydaspes, Alexander's crossing of the Hydaspes river, and the Indians are deceived.

The river crossing was to take place at night, under strict secrecy. At nightfall, Alexander, leading a mixed formation that included units of Greek cavalry, horse archers, Indian foot archers, and half of the phalanx, set out from the camp toward the location where the fleet had been prepared. The troops remaining in the camp were entrusted to Craterus, with orders to strike directly at Por if he moved his elephants away from the crossing.

Alexander's detachment advanced north in complete silence, keeping some distance from the river. That night, the Macedonian king was very fortunate with the weather: a heavy thunderstorm with rain broke out, allowing Alexander's men to reach the rafts unnoticed. The crossing was carried out in three stages, as it seems the river fleet was unable to transport all the soldiers at once.

By morning, when the storm had subsided, Alexander was already arranging his troops in battle formation on the far side of the Hydaspes. He sent his cavalry forward, alongside the horse archers. The Macedonian king mixed the infantry archers with the cavalry and placed the phalanx and hypaspists behind them. In this formation, Alexander led his troops toward Por's camp.

When Por knew of the Macedonian crossing, he initially did not believe the reports. Directly across the river, he saw the Macedonian camp, where it seemed nothing had changed. Nonetheless, he sent a small force of two thousand cavalry and 150 chariots, led by his son, to assess the seriousness of the threat to his army. As soon as this force engaged Alexander’s troops, it was immediately routed, and the young royal son was killed in one of the skirmishes.

Por, upon learning of the situation, realized that Alexander had outmaneuvered him and decisively led his army north to engage the enemy who had crossed the river. At the crossing, he left a small detachment with a few elephants to prevent Craterus from attacking his rear. In the front line of his army, Por positioned the war elephants, which were intended to break through the Macedonian phalanx. Following the elephants were his numerous infantry contingents. On his flanks, Por deployed cavalry units and chariots. Although Por was significantly outnumbered in cavalry, he had the advantage in infantry.

The Battle of the Hydaspes

Alexander opened the battle by sending his horse archers to attack the Indian chariots. They were vulnerable targets, so Por decided to cover them with his cavalry contingents at the front. However, before the Indians could reorganize, Alexander led a decisive charge with the Greek cavalry on the right flank, striking the Indians before they could form into battle order.

To support his left flank and simultaneously engage Alexander, Por ordered his cavalry on the right flank to ride across the entire field and strike at the Greek cavalry. This was noticed by one of Alexander's cavalry commanders, Ken. Taking a squadron of Macedonian horsemen with him, Ken galloped diagonally across the battlefield, planning to strike the Indians from the rear. It took a considerable amount of time for the Indians to reorganize, so Ken managed to intercept them as they approached Alexander’s cavalry. Ken’s small detachment would not have been able to hold off Por’s cavalry for long, but Alexander himself came to his aid, having by then dealt with the Indian left flank.

The phalanx attacking the centre in the battle of the Hydaspes by Andre Castaigne (1898-1899)

Realizing that the battle was not going as planned, Por moved forward with his main asset — the war elephants. Despite the Macedonians firing numerous arrows and javelins at them, the massive animals charged into the ranks of the phalanx, sweeping everything before them. The elephants trampled people, impaled them with their tusks, and broke their backs with their trunks, operating with great effectiveness due to their military training.

At the same time, the Indian cavalry that had withdrawn from the left flank turned and charged at Alexander and his Greek cavalry. At this moment, the battlefield appeared most chaotic: in the center, a cavalry battle was taking place, while on both sides, the Macedonians struggled to hold back the assault of Por’s elephants. Nevertheless, the resilience of the Macedonian formations became evident. Restoring their formation as best as they could, the phalanx soldiers struck at the elephants with their long spears, while the light infantry targeted the mahouts. Many of the elephants, maddened by pain and losing control, turned 180 degrees and began trampling the Indian ranks instead.

The Macedonian phalanx advanced, seizing the initiative on the battlefield, and destroying any resistance. Finally, having exhausted all its potential and suffering significant losses, Por’s army almost completely fled. Many Indians tried to reach their camp, but they met with failure even there: Craterus's troops had already crossed the Hydaspes and were intercepting the fleeing soldiers.

Meanwhile, Por, sitting on his elephant, continued to fight. Alexander sent Taxila to persuade the Indian king to surrender, but Por drove his arch-enemy away, threatening him with a spear. Eventually, Por was forced to dismount and appeared before Alexander. According to ancient sources, the casualties on the Indian side were 3,000 cavalrymen and 20,000 infantry. Alexander's losses were significantly lower: 280 cavalrymen and 700 infantry.

After the Battle of the Hydaspes, Alexander resumed his campaign eastward. Having subdued the opposing tribes of the Kafes, he led the Macedonian army to the river Jhelum, intending to cross it and invade the central regions of India. However, on the riverbank, the soldiers, thoroughly exhausted from the prolonged campaigns and fearful of the countless armies with thousands of war elephants, demanded a halt.

Alexander waited several days for the soldiers to calm down and for the campaign to resume, but the Macedonians showed unprecedented resolve. The king of Asia, who had defeated all opponents in his path, had to yield: the army turned around and headed back. Ahead of the Macedonians was a long, perilous journey back to Babylon.