Purus

Michael Witzel conjectures that Porus was a king of the Pūrus, a Vedic tribe, who existed as a marginal power in Punjab after their defeat in the Battle of the Ten Kings.^[8][9][10] Hem Chandra Raychaudhuri largely agreed with this identification.^[7]

Sourasenis

Quintus Curtius Rufus mentions Porus' vanguard soldiers carrying a banner of "Herakles" during the face-off with Alexander.^[11] Accordingly, Ishwari Prasad and a few other scholars argue that Porus was a Shurasena.^{[12][lower-alpha 1]} This identification is based on the fact that multiple Greek histories — Indica by Arrian, Geographica by Strabo, and Bibliotheca historica by Diodorus Siculus — note Megasthenes^{[lower-alpha 2]} to have described an Indian tribe called Sourasenoi who worshiped one "Herakles" and originated from the lands of Mathura and Yamuna.^{[11][14][lower-alpha 3]}

Background

Porus ruled over the tracts between the rivers Hydaspes (Jhelum) and Acesines (Chenab); Strabo noted the territory to contain almost 300 cities.^[15] He had a hostile relationship with the neighboring polity of Taxila, having assassinated their erstwhile ruler Ambhiraj, his maternal uncle.^[15]

When Alexander crossed the Indus in their eastward migration, probably in Udabhandapura, he was greeted by the then-ruler of Taxila, Omphis, son of Ambhiraj.^[15] Years ago, he had visited Alexander in Sogdiana and was treated as an ally; Omphis' rule was confirmed and gifts lavished, but a Macedonian satrap was installed.^[15] Omphis hoped to force both Porus and Abisares into submission, leveraging the might of Alexander's forces, and dispatched diplomatic missions to this effect.^[15]

In response, Abisares offered submission but Porus refused, leading Alexander to seek a face-off on the bank of Jhelum.^[15] Thus began the Battle of the Hydaspes in 326 BC; the exact site remains unknown and the exact strength of the armies cannot be determined either, due to major discrepancies between sources.^[15]

Battle of the Hydaspes

Alexander re-used the same vessels which were used for crossing the Indus, the first time, some 300 km away at Udabhandapura.^[15] His forces frequently mounted intrusion-attempts and even before the battle had started, skirmishes were reported in the riverine islands.^[15]

A few months later, Alexander decided to accompany a strike force across the densely forested headlands and besiege Porus' defense; the base camp with substantial cavalry and infantry units was left under Craterus, who was advised to follow Alexander upon a successful passage whilst the remaining forces were distributed along the river under three phalanx officers to distract Porus' forces.^[15] The strategy was successful and they crossed the Jhelum unobstructed, on a stormy night, just before dawn.^[15] A band of horsemen on chariots led by Porus' son did detect the intrusion and mount a charge but was repelled by Alexander's superior cavalry.^[15]

Informed of Alexander's passage, Porus became concerned with tackling those who had already crossed, rather than preventing passage of the remaining majority.^[15] He took a defensive position in the plains, interspersing infantry units with elephants^{[lower-alpha 4]} on the front lines and stationing the cavalry and chariots in the wings.^[15][16] Alexander chose to shield his infantry and instead led a devastating cavalry charge on Porus' left wing, forcing reinforcements from the right; however, this rear-transit came under attack by Coenus' cavalry and Porus' cavalry was compelled to take refuge within the infantry frontlines, causing confusion.^[15]

This led to an all-out attack from both sides, but Porus' plans proved futile.^[15] According to Heckle (2014), Porus is believed to have had around 30,000 infantry. However, Porus only had 4,000 mounted troops.^[17] Not only were Porus' cavalry charges repelled but the mahouts were killed using sarissas and the elephants were pushed back into Porus' columns, wreaking havoc on the rear, Alexander's cavalry kept charging and inflicting disorder.^[15] Soon Porus' army was surrounded on all sides, and became easy fodder for Alexander's forces with the cavalry exterminated and most of the elephants captured.^[15] Still, Porus refused to surrender and wandered about atop an elephant, until he was wounded and his force routed.^[15] A fraction of the infantry successfully escaped and probably planned to regroup but Craterus pursued them to their deaths.^[15]

Aftermath

Despite the apparently one-sided results, Alexander was impressed by Porus and chose not to depose him.^[19][20] His territory was not only restored, but also expanded, with Alexander's forces annexing the territories of Glausaes, who ruled to the northeast of Porus' kingdom.^[19] Further, Omphis was reconciled with Porus.^[19]

A joint expedition was then mounted against a territory east of the Chenab, ruled by an enemy cousin of Porus; he had earlier submitted to Alexander but, suspicious of Porus' rise in rank, chose to flee with his army.^[19] The date of this battle remains disputed; Alexander's forces overran his lands before meeting stiff resistance at a walled Sangala on the other side of the Ravi.^[19] Siege warfare was executed to brilliant effect and the full-fledged attack began once Porus had joined with his elephants.^[19] As Sangala and allied cities were razed, Porus was allowed to station his garrisons.^[19]

Thereafter, Alexander proceeded unopposed to the Beas and even intended to cross it towards the Gangetic Plain; however, the monsoon was at its peak and his weary troops remained stubborn despite his cajoling and threats.^[19] A reluctant Alexander had to renounce his plans and turn back.^[19] Porus was thus ratified as the de facto ruler of the entire territory east of the Jhelum, with no European satrap to co-rule with, unlike Ambhi and Abisares.^[19] The crossing-back of the Jhelum was a prolonged affair; filled with festivities, it attracted thousands.^[19]

Death

After Alexander's death in 323 BC, Perdiccas became the regent of his empire, and after Perdiccas's murder in 321 BC, Antipater became the new regent.^[21] According to Diodorus, Antipater recognized Porus's authority over the territories along the Indus River. However, Eudemus, who had served as Alexander's satrap in the Punjab region, killed Porus.^[22]