How Great was Alexander’s Victory over Porus?

Major General Syed Ali Hamid considers the historical evidence and the conditions faced by the Macedonian conqueror in modern-day Punjab

How Great was Alexander’s Victory over Porus?
A journey on the Grand Trunk Road with my father was always punctuated with anecdotes from history. As we headed out of Rawalpindi he indicated the Buddhist stupa at Mankiala where the Sikh Army of the North surrendered in 1849 after the Second Anglo Sikh War. From near Dina we could see the fort at Rohtas which was commissioned by Sher Shah Suri sometime during his seven-year rule commencing in 1538. And as we crossed the mile-long road-railway bridge over the River Jhelum, he told us about Alexander’s battle with Porus 15 miles downstream in the summer of 326 BCE.

With my earlier superficial knowledge of history, I believed that Alexander was invincible. However, around 1998, I read the Indus Saga by Aitzaz Ahsan and became aware that modern historians have taken up alternative theses on Alexander’s invasion, particularly this battle and its aftermaths. There are seven surviving accounts on Alexander which were written between 100 BCE and 200 CE, mostly by Romans but some by Greeks. He is also recounted by other authors during this period and according to contemporary historians, all are full of confusion and contradictions. In fact, as early as the last century of the BCE, the Greek geographer Strabo (born 64 BCE) complained that all who wrote about Alexander preferred the marvelous to the true. The Anabasis of Alexander written by Arrian is considered the best source on his campaigns. But Arrian was clearly a great admirer of Alexander and since his account was written 450 years after Alexander’s death, it suffers from the same errors and pitfalls.

Sketch of the Battle of the Hydaspes (Jhelum), showing best- and worst-case scenarios for Alexander's manuevre to surprise Porus

Having spent two-and-a-half years conquering present d-y Afghanistan and the kingdoms astride the River Oxus (Amu Darya), Alexander of Macedonia turned towards the subcontinent of India in the Autumn of 327 BCE. Ostensibly he was seeking the Great Outer Sea at the end of the world and to outdo the conquests of the legendary hero Heracles. However, he also wanted to secure the furthest limits to which his arch rival, the Persian Empire had extended that was driven by an economic motive. According to Herodotus, considered the father of history, Darius the Third (550–486 BCE) was the first of his dynasty to impose a regular yearly tribute on the 20 satrapies (provinces) in his empire. Of all these, the satrapy of the Indus which encompassed most of present-day Pakistan was the most densely populated and provided the largest revenue – 360 talents (13,000 kilos i.e. 14 tons) of gold dust.

Alexander’s army of 50,000 marched down the River Cophen (in some accounts identified as River Kabul) in the Autumn of 326 BCE and at Jalalabad divided into two. Most of the tribes within the Khyber Pass and beyond in the Cophen valley had submitted their allegiance and half of Alexander’s army headed towards Hund to prepare for the crossing of the mighty River Indus. With the rest, Alexander penetrated into the mountains of Assacani (Dir, Bajur and Swat), aiming to protect his flank from damaging raids by subduing the hostile and warlike tribes. It would prove to be a costly undertaking and probably more than what Alexander had anticipated particularly the battle at Massaga (near Chakdara) which lasted four days and ended with a mass slaughter of the defenders after they were enticed to surrender. It was the type of terror tactics replicated by the Mongols to discourage any subsequent resistance. However, neither were the defenders at Ora (Udigram), nor those at Bazira (Barikot) or at the famous Rock of Aornus (the 2,550-metre mountain of Pir Sar on the Indus), prepared to submit without tough battles. Thus when he finally arrived at Hund after a six months’ arduous winter campaign in the mountains during which he had to subdue two highland citadels, his half of the army must have been quite depleted and exhausted.
It was a much lighter force with enhanced mobility – but probably better suited for the fluid battle of the steppes that Alexander had been fighting for the past two years than the pitched battles that he faced as he crossed back over the Hindu Kush into what is today Northern Pakistan

This may have been one of the reasons that he decided to rest his army and winter on the northern bank of the Indus, but there were others. He had to detour back to Nysa (west of Dir) to suppress a revolt and besiege Peucelaotis (Charsadda) for a month before it capitulated. With all these delays, he arrived in Taxila in the Spring of 326 BCE and with the monsoons imminent, he was faced with a choice. He could either wait in Taxila for the next four months for the rains to subside or surprise Porus on the Hydaspes by attacking during the rains. It was a tactic that he had applied before but I can’t help feeling that he was driven more by impatience (and he was an impatient commander), than a rational decision – and that the timing had been forced on him due to unexpected delays in getting to the Indus.

The army that Napoleon had at his defeat at Waterloo in 1815 was not the same army that he maneuvered to a brilliant victory ten years earlier at Austerlitz. It had been practically annihilated in its retreat from Moscow and raised afresh after he escaped from Elba. Similarly, Alexander’s army was not the same with which he had won a decisive victory against Darius III at Guagamela four years earlier in 331 BCE. Since then no new Macedonian troops had been received and 14,000 of the reinforcements from Greece had been left to supervise the two new and rebellious Satraps of the Oxus. Only three-fifths of the army were Hellenic Europeans and the elite Companion Cavalry (Alexander’s shock troops that he personally led), had shrunk from a strength of 2,600 at Guagamela to 1,800 Macedonians. As Alexander’s force campaigned towards India, Orientals played an increasing role in the hipparchies (regiments) of the Companion Cavalry. The army was swelled with the horsemen from Iran as well as Steppe nomads from Bactria and Sogdia (north and south of Amu Darya) and 4,000 archers including 1,000 on horseback. It was a much lighter force with enhanced mobility – but probably better suited for the fluid battle of the steppes that Alexander had been fighting for the past two years than the pitched battles that he faced as he crossed back over the Hindu Kush into what is today Northern Pakistan.

A diorama at the Army Museum, Lahore, showing Porus' elephants fighting Alexander's infantry

The ancestor of the Grand Trunk Road was the Uttarapatha (trade route) that ran along the River Cophen (Kabul), to Peucelaotic (Charsadda), across the Indus to Taxila, in the direction of Sangala (Sialkot) or Labokla (Lahore), and beyond, to Patna on the plains of the Ganges. Till the 16th century CE it followed the Kahan Nala as it broke through the Pabbi Hills at the Rohtas Fort, to a ford on the Hydaspes 10 km below Jhelum. This was the natural site for Alexander to initially assemble his army and its appendages. Up to the Middle Ages behind an army on the March came an equal if not more camp followers – tradesmen, craftsmen, families and so on as well as baggage animals, herds of cows and sheep etc. etc.

During my military service I have served in Jhelum and Kharian for seven years and know the terrain intimately on both sides of the river. Scholars have proposed sites further downstream (at Haranpur and Jalalpur), but the approach towards these sites dropped down from the Salt Range through even more fractured and eroded terrain than astride the Uttarapatha. They could have been crossed by the army but not by the host of followers. Additionally, paleo-hydrological research indicates that Hydaspes was far from these places until the 8 century CE.

There were four phases of the overall battle. The first was the arrival of Alexander on the Hydaspes in the spring of 326 BCE and for two months preparing to cross while making feints to lull Porus into complacency and the belief that the crossing would be after the monsoons. The second was the reconnaissance and buildup by a maneuvering force for a surprise crossing upstream during the end of May and reassembling for battle. The third was the battle. And fourth and final, the crossing by the main army and the destruction of Porus.

Of all these phases, the most critical and on which depended the success of the battle was the maneuver well on the flank to develop a double threat to the army of Porus. The point of application of this maneuver was above a bend in the river 15 km to the north where vessels could be concealed in a forest that reached to the shore. Historians who subscribe to the success of this crossing of the Hydaspes during the monsoons, cite Alexander’s passage into Asia Minor over the Hellespont (Dardanelles) as an example. At its narrowest, Hellespont is only 1.6 km wide and to transport his army of 4,000 cavalry and 30,000 infantry, during an unopposed crossing, he assembled a fleet of 150 (90-oar) trireme-type vessels. On the other hand, in the maneuver across the Hydaspes, he apparently transported 5,000 cavalry and 11,000 infantry with only 30 (30-oar) triaconter galleys and boats (that had been disassembled and transported 200 km from Hund), as well as rafts made from tents, leather and straw. Presuming that on an average each galley, boat and raft carried 20 soldiers, the river crossing would have needed a fleet of 1,300 vessels. If the troops crossed in three waves as recorded, each wave would have comprised of 450 vessels.

Having considered the mathematics of the troops and vessels, I consulted Major General Pervez Akmal on the mathematics of the crossing. Akmal had a distinguished career in the Army Corps of Engineers and was well versed in the theoretical and physical dimensions of river-crossing operations. All contemporary maps showing Alexander’s crossing draw a straight line across the river taking no account of the effect of the velocity of the water. The rains had been heavy - the monsoon had been early - and the Hydaspes, already swollen in May with melting snows, was probably about a mile wide. As it debouched from the mountains with a velocity close to 8 knots, it would have carried a lot of debris including large tree trunks from the dense pine forests upstream. To maintain cohesion during the crossing it is said that each galley/boat towed 10-15 rafts but that would have only taken care of the major portion of the first wave. Could the galleys have returned to tow the rafts of the second and third wave. Akmal says it was not possible. The 30-oar triaconter had a maximum speed of 8 knots and against a current of the same velocity, the galleys would have stood still.

Victory coin of Alexander being crowned in Babylon and attacking Porus on the Hydaspes­

Akmal was also of the opinion that even a modern army would desist from crossing under these conditions. In his reckoning, an army two millennia ago attempting the same would have paid a heavy price. The rafts of the second and third wave that survived the rough passage and debris, would touch the far bank far downstream, spread haphazardly for 2-3 km, with many troops floundering ashore from capsized vessels. Similar would have been the fate of the 3,500 horses of the two waves tied tougher in teams of ten for swimming across the fast and very cold water. With his army scattered along the river bank Alexander would hardly have been in a position to give battle and would have sued for peace. In the legend having won a great victory, he magnanimously returns the kingdom to Porus. This was propaganda to retain support back in Macedonia by transmitting back news of great victories.

Two months later Alexander with his army arrived on the River Hyphasis (Beas). The army had been lashed by the monsoon since it left the Hydaspes. Everything that could rust, rot, mold or corrode did especially the leather and weapons. And the snakes driven out by floods were everywhere that the soldiers camped. The got into beddings and cooking utensils and concealed themselves in every nook and cranny. There were pythons 25 feet long, cobras and kraits. Just as the forests and rainfall of Western Europe wore down the Umayyad Army penetrating into France in 732 CE, similarly Alexander’s soldiers were worn down not only by the excessive fighting but by the incessant rains, jungles, rivers and snakes. Fatigue drained the men’s morale. Rumors flew about the camp near the Hyphasis that the kingdoms ahead could muster thousands of war elephants and hundreds of thousands of tough soldiers. The prospects of facing an army far larger than that of Porus was too intimidating and the soldiers refused to go further. Alexander addressed the officers but the response from the soldiers was a deafening silence. After brooding for a few days, Alexander relented and retraced his steps to the Chenab from where he headed down to the Arabian Sea and back to Babylon.

In the late 19th century, an amazing discovery was made in Afghanistan.  Called the Porus Medallion, the coin commemorates Alexander’s victory at the Hydaspes and he can be identified by his wielding the thunderbolt of Zeus and the distinctive plumage which Plutarch tells us the king wore on either side of his helmet. On the elephant stands Porus – his size relative to the elephant indicating that he was very tall, over 2.2 meters. If minted before Alexander’s death in 322 BCE, it would be his sole surviving depiction produced in his lifetime.

It would also be one of the first example of using coins as a form of propaganda, in this case probably false – what in contemporary language would be considered as ‘fake news’ of his ‘great victory’ on the banks of the Hydaspes.