Monday, December 4, 2023

The Jhelum


Alexander's Last Battle

June, 326 BCE

Also called the Hydaspes

Macedonians under Alexander III of Macedon,  approx. 26,500 (5,800 cavalry, 22,200 infantry)
Indians under  Porus, Raja of the Pauravas,  approx. 32,000 (2,000 cavalry, 30,000 infantry, 85 elephants, 240 chariots) 

Sunrise: 04:43  Sunset: 19:11  
(approximate times calculated from NOAA's Sunrise/Sunset Calculator based on location. However as the calculator does not figure for dates prior to 1700, this was based mid May for this year. It may have been a few minutes off. 

Weather: Monsoon came early this year, apparently. Very rainy from snowmelt off of the Himalayas. The Jhelum River was swollen and wide. Ground on either side was soggy.

Approx. Location: 32°35'18" N, 73°20'54" E  Near modern city of Mandi Bahuaddin, NW Punjab, Pakistan

This was to be Alexander the Great's last major battle, though he didn't know it. (Wait! That's not a spoiler. He wasn't killed here. Geeze! Leap to conclusions, why don't you!) But other factors eventually persuaded him that his youthful pastime of endless slaughter and conquest had reached its nadir. He needed a new hobby.

This story, too, is another example of how ancient history narratives can be bent by ancient propaganda, leading us to doubt their veracity. Once wonders if tales of events in our current times will be understood,  or believed in 4349 (the same distance to the future as we are to this battle in the past). That's assuming the human race is still here in 2349 years. But, with that major caveat, let's get to this event...

For eight years since his invasion of the Persian Achaemenid Empire, starting with  the Granicus in 334 BCE, the boy king had won battle after battle, suffered innumerable wounds, caused hundreds of thousands of deaths, overthrown the reigning Great King, Darius III, and continued to push farther and farther east, past the Indus River, to the subcontinent of India. 

In his youth he had studied at the knee of the great Aristotle, who had told him that the earth ended in the east at the world-encircling Ocean, just past what is now Afghanistan and the Hindu Kush mountain range. Greek mythology had that both Dionysus and Heracles had conquered this unknown land, and now Alexander wanted to outdo that god and godette by going farther east and, I presume, surfing in that reputed Ocean,  preminiscent (OkaymI just made up that word) of Col. Kilgore in Apocalypse Now

Strategic moves at the River Jhelum prior to the battle. While there doesn't seem to have been an actual settlement at the site of Jalapur (an important place in the narrative below), I have labeled it in a parenthesis.. After the battle Alexander supposedly founded a town there, naming it after his soon-to-be-deceased horse, Bucephalus, Boukephala. Apparently it received its current name, Jalapur Shafir during the reign of the Mughal Emperor Akbar sometime in the 16th century. More than you wanted to know...okay...I'll stop here.

To get us to this particular battle, Alexander had not been back to his home in Macedonia in over eight years. Nor had most of his army, the ones who were still alive, anyway. After his first battle at the Granicus in 334 he spent eight more years conquering all of Darius's empire, defeating the Great King in two big battles (Issus and Gaugamela) and taking a long side trip down through Palestine, conquering city after city (yes, including Gazathat poor city hasn't had a break in 5,000 years), into Egypt. The Great King Darius III never formally capitulated to Alexander, but withdrew eastward to try and raise yet another army to face him. Darius, though, was treacherously assassinated by a couple of his own satraps in 330, so Alexander never had the satisfaction of having him bend the knee to him, acknowledging him as his successor. Alexander thought that would've somehow given him legitimacy and it pissed him off...royally.

After occupying the great cities of Babylon, Susa, Ecbatana, and burning the capital Persepolis to the ground (out of spite for the ancient Greeks' nemeses), Alexander continued his quest farther east to subdue that extreme edge of the Achaemenid empire. He marched along the southern coast of the Caspian Sea, into Parthia, Bactria, Sogdiana, across the Hindu Kush range, into today's Afghanistan; founding innumerable cities named after himself, coercing local satraps and rajahs to perform proskynesis (prostrate themselves, literally), and exterminating those who resisted. His goal was to continue past the easternmost frontiers of the Persian Empire at the Indus river, farther than anyone (including Heracles or Dionysus in legend) had ever gone, to the shores of the World Ocean. Just like Aristotle had promised it would be there.

Needless to say, his troops were pretty tired and just wanted to go home. They had marched some 11,679.29 miles since leaving Pella (or 18,796 for you metricophiles--and yes, I calculated this myself using Alexander's route and Google maps.)  They'd had all the booty they could carry. And this vacation took far longer than any of them had signed up for.

Alexander reaches the far end of the Persian Empire

By the time his army had crossed the Indus River (in the Punjab), Alexander had acquired an Indian ally in one Raja Ambhi of Taxila (near modern Rawalpindi, Pakistan). Taxila was the easternmost satrapy of the empire and after word of Alexander's defeat of Darius and the fall of the Achaemenids reached him, Ambhi had taken this opportunity to make himself raja and set up his own independent kingdom.  Ambhi was, at the time, also a mortal enemy of the raja of the Pauvaras, Porus, and saw in his convenient alliance with Alexander a way to defeat his enemy for good. He met Alexander on a plain outside Taxila and offered his army, his elephants, and his hospitality.

 The Macedonian king, who had arrived in Taxila in early February, spent the next few months resting his army there, enjoying the bountiful countryside (including some rare wine that was grown in the hills surrounding, apparently unique this east in Asia), and partying in the best Bacchic tradition. Ambhi was a good host.

Alexander had meanwhile sent word to Porus and to Abisares, another raja to the north of the Pauvaras that he wished to meet with them, ostensibly to bring their kingdoms under his protection. Abisares prevaricated, accepting some gifts that the westerner had sent him and sending back obsequious ambassadors assuring Alexander of his submission, but using the time to build up his own army. Porus said he would very much like to meet Alexander, but with his whole army, at the border of his kingdom on the Jhelum, in full battle array. Neither Porus's nor Abisare's kingdoms had ever been part of the Achaemenid Empire and they weren't about to start now, thank you very much.

When he got this bellicose reply from Porus in early June, Alexander also received intelligence that Abisares, in spite of his thank you letters for all the gifts and his protestations of loyalty,  was also heading south with his army to join Porus. (That duplicitous son-of-a-bitch!) The king had to act now. He formed his army, packed up the pontoon bridges over the Indus, and marched them all south to attack Porus as fast as they could

Unfortunately, Alexander was apparently not appreciative of the regular onset of the South Asian monsoon, which started up in June this year. So his army had to slog 104 miles (167 km) through mud, through the Nandana Pass, to arrive at the likely crossing of the Jhelum before Abisares got there to join Porus. Reportedly, according to Peter Green, they did it in two days! Towing their pontoons and trireme ships! What's a little rain to these gnarly bastards?*
*I'm not buyin' it. Peter Green, in his biography of Alexander (see references below) cites this two-day figure from Pliny, a Roman historian who, three centuries after the fact, evidently got it second-or-third-hand from some of Alexander's obsequious press-hacks, who were notorious for exaggerating The Boy Wonder's feats. Marching 104 miles in the driving rain, and mud, through mountain passes? In normal weather, on flat, dry ground the average adult human can walk about thee miles per hour. So 104 miles would've taken some 35 hours in clear weather with dry roads. That's non-stop, without restand pulling wagons and boats and hundreds of tons of arms and armor. Also the boats and pontoons had to be dismantled and dragged another 29 miles (46.67 km) overland from the Indus to Taxila.  His army may have been in good shape, but they weren't Marvel Superheroes. Also, neither Diodorus nor Arrian mention this incredible marching speed; they both just say the Macedonians hurried to the Hydaspes.

View from hills above Jalapur Sharif, Pakistan, looking south toward Alexander's fording site across the Jhelum, which you can just make out in the hazy distance. This is probably the sight Alexander first had of the limit of his newly acquired empire as he emerged from the Nandana Pass. Image from Google Maps, Mohammed Zohaib.

Nobody counted on the river being so wide, though.

The Jhelum was the very eastern border of the Persian Empire, the beginning of India proper. When Alexander's army arrived at the logical crossing at Haranpur (see map), they were alarmed at how wide the river was (a mere tributary of a tributary of the Indus). The melting of the snow off the Himalayas and the monsoon rains had turned it into a churning flood. Just across the river, Alexander could see the massed army of Porus, including his 85 (or 200, depending on whose narrative you believe) war elephants, trumpeting menacingly and just waiting to trample whoever waded ashore. 

Alexander decided to set up camp around Haranpur and wait for his pontoon boats to arrive from the Indus (ready to reassemble in their Ikea boxes). Meanwhile he had his men patrol up and down the river, looking for other unguarded crossing points. Porus, at the same time, had followed these patrols from his side of the river, setting up guard posts for miles to warn him of any attempted crossing. He and his army knew this terrain far better than these Western invaders. 
View from the southside of the Jhelum today looking north toward Haranpur. This part of the river, even 2,350 years ago, was a traditional crossing point due to the shallowness and slow flow here; so much so that two millennia later, during the British Raj period in the 19th century, engineers picked it to build the first railroad bridge over the river.  Image from Google Maps, Billu FF


At the same time, recognizing that he may have to wait until the monsoon ended in the fall (as his own Indian allies advised him), Alexander made ostentatious show of bringing in hay and provisions to his camp, all in plain sight of Porus. According to his Roman era biographers, this was all part of Alexander's genius in lulling the Indian monarch into complacency, as were all the show attempts to cross the river at various locations. Eventually Porus, witnessing all the settling-in activity around the Macedonian camp and boring of Alexander's futile attempts to cross the river, concluded that nothing was going to happen until the rains stopped. He slacked off and stopped chasing the Macedonians up and down the opposite shore. He did, though, keep his system of guard posts in place, for miles up and down the river, each a shout's distance from each other. Porus wasn't an idiot. And his troops were experienced warriors.
Porus also knew, in spite of the invincible reputation of the Macedonians, he had a secret weapon: his elephants. Elephants had been part of South Asian warfare for centuries. They were the tanks of the ancient world. Alexander's troops had first encountered elephants in battle at Gaugamela, where Darius had deployed some, but not in the numbers or as aggressively as Porus would. And Alexander had noted that his own horses, unused to these gigantic monsters, panicked at the sight of them, refusing to charge forward. He noted this again when, as Ambhi had met him at Taxila in February, that that raja's own "friendly" elephants had seemed to unnerve his cavalry. So the last thing Alexander wanted to do was attempt a crossing of the Jhelum in the face of 85 (or 130 or 200 depending on the source) of these monsters. 
Eighteenth century illustration of a contemporary Indian war elephant, not much different from what they had probably looked like for two thousand years (though without chain mail armor). Though war-elephants from the  Punic and later Hellenic Period wars had howdahs (wooden towers) on top, the Indians apparently didn't use these cumbersome contraptions, at least in battle. Most of their elephants had a human crew of two, a mahout (driver) on the animal's neck and a warrior seated behind, both armed with bows and long lances. Foot soldiers would flank the beast, protecting it from enemy soldiers trying to hamstring or spear it from the side or back, much like modern infantry support tanks today.  Unknown artist from C1750, Philadelphia Museum of Art

For an unspecified number of days or weeks, this routine went on; the Macedonians making demonstrations on the north bank, the Indians making counter-demonstrations on their side. But Alexander's local guides had revealed to him a practical and concealed crossing point some 17 miles (27 km) upstream, at a place that would later be founded as a city by Alexander, Boukephala, (after Alexander's soon-to-be-deceased horse) and later, in the 16th century, renamed Jalapur Sharif .
The area was hidden in a nullah (a local word for ravine) formed by a stream, the Kahan Kas. The Jhelum River was pinched off back then by a large, wooded island called Admana, concealing activity from the opposite bank. Alexander had his boats carted up the road one night from Haranpur and reassembled in the nullah, ready to launch into the narrow river on the near side of the Admana Island. The next day he marched his cavalry, his Hypaspists (the Royal Foot Guard), two taxeis of his Phalanx infantry (6,000 heavy infantry, a taxis is like a brigade, composed of six syntagma, or battalions, of 256 men each), three thousand of his light infantry from his main camp up to the nullah. While he did this in apparently broad daylight, their movement was concealed due to a particularly strong thunderstorm that day and the overland route of march was at least three miles beyond the river, so the noise, potential dust, and even sight of the moving host would not have been detected by Porus' outposts on the far side of the river. According to Plutarch, though, the storm was so frightful that many men were "burned to death by the thunderbolts" (play Wilhelm scream here). To further mask his move from Porus,  Alexander had a look-alike dressed up in a replica of his famous royal cloak, galloping around the base camp at Haranpur and moving in and out of his royal tent. He had left Craterus back at the original crossing site to make loud demonstrations with over 9,000 men to conceal his real flanking movement. And he had Meleager, with three additional taxeis of infantry (4,600) covering the lower passages across the river between Haranpur and Admana Island, ready to ferry across to reinforce the main army should it successfully engage Porus. 
Those of you who have read my previous article on Alexander's first battle at the Granicus will recognize this strategy as a natural evolution of his ploy in that battle: diverting his enemy with a show of activity on the opposite bank of the river, while secretly crossing upstream to outflank him. It's been a ploy that countless generals have used since, explained in the first Jurassic Park movie where Muldoon describes how one velociraptor distracts her prey from the front while the other attacks from the side. So I guess you could say the trick is millions of years old.

At dawn the rain had eased a little. Loading all of his infantry on the assembled boats, and his cavalry on rafts that his men had stitched together from cowhides and stuffed with hay (this works?), Alexander launched his force down the western channel of the river, concealed by the woods of Admana Island. Everything went well. When this flotilla floated down past the southwestern tip of the island, it turned toward the opposite shore and landed. 
Only problem: it wasn't the opposite shore but another island in the stream. Oops!  So they had to then spend valuable time looking for still another fording site from here to the actual bank. When they finally found it, the men had to wade across up to their chests. Arrian says that this ford was so deep that the horses had could barely keep their heads above water, which, if you think about it, seems to contradict his previous depiction of men wading up to their chests. Unless the horses were Shetland ponies.

Of course, by this time, the Indian lookouts on the opposite bank saw what was happening and sent messengers galloping downstream to alert Porus. Actually, though it isn't described in any of the narratives I researched (Arrian's, Diodorus', Plutarch's, Green's), I was troubled by the timing. It would've taken almost an hour, even on dry ground, for a horse to gallop as far as Porus' camp (17 miles, 27 km, 136 furlongs, 180 stadia). So I'm speculating that this is where the Indians' chain of watch-posts came in, with those manning them passing on prearranged signals, by fire, flag, drums, or horns; sort of like my favorite scene (one of them) in Peter Jackson's third Lord of the Rings movie, where the chain of signal beacons alert Rohan of Sauron's attack on Minas Tirith. At least that's my fantasy. But I wasn't there (neither were Arrian, Diodorus, Plutarch, or Peter Green), so it may have just as well been a Pony Express delivering the message.

Porus, getting this warning, not sure if this was a main attack or another diversion, sent one of his sons with a thousand cavalry and some chariots over to make a reconnaissance-in-force, enough, he thought, to catch the Macedonians as they were emerging from the water and before they had had time to get in formation.There were at least three versions of what happened next. In one version (related by Aristoboulos) Porus' son (let's call him Porus the Younger, or P2) came up with only sixty chariots to reconnoiter but not engage, then turned and dashed back to report the bad news to his dad. In the second version, P2 came up with a larger force as Alexander was emerging from the water with his cavalry.  In this telling P2 personally wounded Alexander, and killed his horse Bucephalus.* But in the third accountthis one by Ptolemy, who was there, and whom Arrian trustsP2 went up with two thousand cavalry and 120 chariots and a major cavalry battle took place, in which P2 and four hundred Indians were killed and all the chariots (stuck in the mud) were captured. The survivors hurried back to warn Porus and deliver the bad news about his son. 
 *Though the death of Bucephalus in this battle is certainly the most glorious, and the one depicted in the 2004 movie Alexander by Oliver Stone, the poor horse may have already died of old age by the time of this battle. He was thirty, after all.  My hunch is that, as much as Alexander was supposed to have loved him, he probably didn't ride him into combat. He did have other horses.

Reprise of the strategic map at the top, so you won't have to keep scrolling up. Isn't that considerate of me?

Porus, hearing this bad news, immediately mustered his army and started marching east to intercept Alexander. He left an indeterminate number of troops and some elephants at the Haranpur ford site to watch Craterus—none of the research I had described how many or the composition of this reserve—and marched with the rest of his army and either 85, 130, or 200 elephants (I'm going with the smaller number since ancient accounts tend to exaggerate).. He stopped at a place along the bank of the river that was sandy and not so muddy; his people knew this ground like the backs of their hands. Peter Green speculates that this site must have been between the villages of Malakwal and Nurpur (see map above). The constant rain and muddy ground would prove to be a tactical problem, though, for his chariots and his archers—a little tease of what's to come.

Meanwhile, once Alexander had disposed of Porus the Younger farther upstream, he decided to take the rest of his cavalry, with all his light, bow-armed steppe riders, westward and intercept Porus the Elder. His infantry he left to follow. Alexander wanted time to let his infantry come up and time for them to rest (they'd been marching in the mud all the previous day, and their ford across the Jhelum had been pretty stressful, poor babies). His goal was to eliminate the threat to his infantry by Porus' cavalry. So he launched a preemptive strike with his Agema ila (squadron) of elite Companions, his four hipparchies* of heavy cavalry, and his Scythians, Bactrians, Sogdian, and Dahae mounted bowmen, 5,300 hundred of the finest cavalry in the world. 
*A hipparchy. 500 men,  is equivalent to a cavalry regiment, composed of two squadrons (ilae) usually arranged in a wedge formation. See my post on the Battle of the Granicus. 

It was also during this phase of the coming battle that Meleager, with his three taxeis of infantry, ferried across the Jhelum to join the rest on the left bank. Since the river was in spate, and supposedly only fordable at the Haranpur and the Admana Island places, it isn't clear when or how these reinforcements came across the river. It is possible that, after Alexander had landed further upstream (on the unexpected island) that he had sent his fleet of boats down for Meleager to use. Or it is also possible that Meleager had his own boats. At any rate, Alexander's infantry was now up to seven taxeis of heavy troops (10,680) and approximately three thousand peltasts and archers.
Ground in approximate location of the battlefield, on the south bank of the Jhelum. The land here was relatively flat and peppered with light scrub forest,  partially obscuring any formations more than a few hundred yards away, at least from ground-level. Image from, by Jona Lendering.

Porus gets ready.

Meanwhile, Porus had been marching his army up the left bank to meet Alexander. When he reached the preselected zone that was sandier, not as muddy, and relatively clear of trees , he deployed to wait for Alexander. He didn't want to tire his own troops out. In the center he aligned his twenty-or-thirty thousand infantry in a fairly deep formation, about three thousand yards wide, but interspersed in the thirty-yard spaces between the elephants in front of them. On either flank he split both his cavalry and chariot forces. In front of the infantry he spread out his eighty-five elephants, about thirty yards apart from each other. Arrian describes the formation of the Indian army as looking like a fortress, with the "curtain wall" of infantry interspersed between the "towers" of elephants.  The idea was, in Indian tactics, to have the elephants carry the main assault, supported in the interstices by the lightly armed infantry, much like in modern warfare where infantry support tanks. Porus himself, mounted on the biggest elephant, positioned himself on the extreme left of the elephant line, from where he could observe, direct, and be seen by the whole army.
Arch over the Southern Gate at the Great Stupa of Sanchi in India, 3rd century BCE, showing the look of warriors, chariots, and war elephants of this era. They may not have had much armor, but they had fetching earrings.  From Wikipedia "Siege of the Seven Kingdoms " over the south gate of Stupa 1 at Kushinagar.

Before long, Porus saw the Macedonian horse start to appear, galloping through the trees toward him. Alexander had a lot of cavalry.

Alexander, leading his hipparchies of Companion cavalry through the scrub woods, came upon Porus' host on the latter's left flank, close to the river. He ordered his light cavalry, all the approximately three thousand mounted bowmen of the Central Asian Steppe to advance and shower the Indian cavalry and chariots with arrows. Porus, seeing how his own cavalry and chariots on that flank were outnumbered  and that Alexander seemed to have massed all his cavalry on that side, ordered his right flank cavalry to gallop behind the army and join the battle on the north side. Alexander, seeing this, then ordered two of his  hipparchies (Coenus' and Demetrius') to move south, and follow the Indian right wing cavalry up the back of their army, taking all of Porus' cavalry in the rear (see map below). Why Porus or any of his commanders didn't notice this move is a puzzle. Also I'm not sure if Alexander, who was himself engaged in the lead of his Agema cavalry squadron, was in a position to notice the move of Porus' right flank cavalry, two miles to the south. Realistically, he probably already had the plan to detach Coeius' two hipparchies in a sweeping move from the beginning, probably to engage that wing's horse, and they just continued to follow those up the backside of the Indian host when Porus ordered them north.

When Porus' outnumbered cavalry started getting the worst of it, even after their reinforcement from the southern flank, and when they realized they were hit from front and back, they all retreated to the shelter of the elephants. They knew that Alexander's horses were terrified of these beasts and could not be persuaded to approach them, whereas the Indians' horses had long been used to elephants, so their presence was a refuge...for a time.

It was about this time that the five taxeis the Macedonian main phalanx, led by Seleucus with the two taxeis of Hypaspists (or Foot Companions, Alexander's "Grenadiers"), began its assault on the Indian center. These were proceeded by the three thousand or so Agranian peltasts and Cretan archers, who swarmed ahead and began unleashing missiles at the oncoming elephants and their riders.

Opening phase of the battle proper. Alexander moves with all his cavalry against the left wing of Porus. In reaction, the raja orders his right wing cavalry to reinforce his left, hoping to counter Alexander's cavalry. Alexander sends the hipparchies of Coenus and Demetrius to move across the Indian front and follow their cavalry clear up the backside of their army to attack the Pauvara cavalry from the rear. The Macedonian infantry hang back. For now.

Squashed brains and exploding guts! Cool!

In dealing with the formidable threat of war elephants, one of the tactics that the peltasts and archers had learned at the Battle of Gaugamela five years before, as well as from their recent Indian allies at Taxila, was that if they managed to bring down the mahouts off the elephants' necks, the animals would become panicked, turning into as much of a danger to their own people as the enemy. So this they started to do. Of course, the Indian infantry between the elephants, also armed with javelins, long swords, and longbows, fought back at the Greek light troops, to protect their "tanks". Other Greek peltasts bravely rushed in to stab the pachyderms in their sides and stomachs, and to slash at their legs with axes and curved swords, hamstringing them. Diodorus luridly describes the carnage as maddened elephants squashed bodies into pulp, or picked them up with their trunks to smash them to the ground, or gored them with their tusks. But one by one the elephants panicked as they were tormented and wounded and their mahouts killed. The poor, frightened animals turned out being even more deadly to their own side as the enemy.
Peter Green postulates in his description of the battle that the Indian bowmen, who had long, bamboo bows, had failed to string them before the battle, waiting until the last minute to attempt to do so, but that the muddy, slippery ground made this extremely difficult. He also described that the manner in which the Indians had to anchor the bows on the ground to aim them was hindered because, again the mud made them slip. The Cretan archers, as well as the Central Asian mounted archers, had smaller, compound bows which could be loaded and reloaded fast, and shot with deadly accuracy and high penetration energy. This disparity in archery effect between the armies reminds me of that between the English longbowmen at the Battle of Crécy (of which I have written earlier) and the Genoese crossbowmen in French service, where the former had kept their bowstrings dry under their helmets during that day's earlier rainstorm, quickly restringing as soon as the rain had stopped, and the Genoese had left their crossbows strung, so they were wet, limp, and essentially useless.  In both battles, little details like this seemed to have made the decisive difference.

After the battle between Alexander's light infantry and the elephants had been going on for awhile, the Macedonian phalanx, having locked shields and assumed a tight formation, finally came up, their sixteen foot sarissas lowered, their front bristling with sharp points for a depth of twelve feet. As
Macedonian phalanx in attack formation, the first five ranks
lowering their sarissas to form an impenetrable barrier.
The following eleven ranks held their sarissas upright, where their
 wavering served as a kind of force field to deflect incoming arrows.
Illustration by F. Mitchell from Wikipedia article on sarrisas.

Xenophon had pointed out in his Anabasis, while horses would not voluntarily impale themselves on a hedge of pointy pikes, neither would elephants. It must have taken some grit for the Mace-donian infantry to go up against these huge beasts, but their discipline and recent experience with elephants at Gaugamela stood them fast. Soon the big animals had lost most of their human crews to the Agranian and Cretan missiles and they began to back away from the phalanx and into the tight formation of their own infantry and their own cavalry who had taken refuge behind them, with disastrous effect to the Indians.

While this was happening to the front. Alexander's cavalry, which had routed Porus' horse, had wrapped around the northern flank and rear of the Paurava foot and started stabbing and slashing at them. Indian infantry in this age were not generally armored as the Greeks were. They had long hyde shields but most of them (except for some elite Kshatriyas, or warrior caste) had no helmets or body armor to protect them. So while they were fleet and nimble, they were terribly vulnerable to heavy cavalry lances as well as Steppe horse archers. While the ancient texts seem to indicate that the Indian foot soldiers were well-trained professional soldiers, they also note that in open battle they did not fight in tight formations, as the Greeks did, but loosely deployed, so they could dash in and out of combat individually. Consequently, they were more vulnerable to cavalry and the tightly packed phalanx of the Macedonians.
The result was that Porus' army was hemmed in, and the rout happened like any avalanche; first in "pebbles" of ones and twos, then handfuls, and then in a rush of thousands, especially as their own elephants were turning and crushing them. Eventually Porus recognized that things were not going so well. He rallied about forty surviving elephants to him, mounted on the largest himself, and personally led a counterattack on the Macedonians. Unfortunately, he was a very large man and an easy target (Diodrous describes him as five cubits in height, or over seven feet, and Arrian say he was over eight feetundoubtedly another exaggeration from antiquity). Diodorus writes that he was shot off his elephant by a peltast or archer and fell wounded to the ground. Arrian records that he was shot so many times he became weak from loss of blood and turned his elephant around to retreat, but staying on top of it. Because he was so conspicuous, his falling or retreat was the trigger the rest of his wavering army needed to call it a day, and everyone started running as fast as they could.

Arrian mentions that Craterus suddenly showed up with his two taxeis of Macedonian infantry and Greek mercenaries in the rear of Porus' army, catching the fleeing Indians in their rout and joining in the slaughter. Now Craterus had specific orders not to attempt a crossing unless Porus' elephants and reserve he had left to guard the crossing had vacated, or that he could see that Alexander was driving back the enemy. Arrian does mention that Porus had left a reserve force to hold the crossing, along with some elephants, though not how many. However if he had 85 elephants at the main battle and started off with 130, well you do the math (no, I'll do the math; 45 elephants facing Craterus). And if the battle proper had been fought eight or nine miles to the east, as has been speculated, the outcome would not have been apparent to Craterus through the trees. So this is another one of those fuzzy details of this battle that has eluded me. He may, however, have noticed the increasing flood of fleeing Indians, and Porus' reserve on the opposite bank may have also started retreating, caught up in the panic. At any rate, Arrian reports that Craterus did cross the river and killed more retreating Indians, completing the victory. 

Was this the victory we have been led to believe?

Arrian writes that Porus lost 20,000 foot, 3,000 horse, and all his chariots. He does not say how many elephants were killed but that all the survivors were rounded up and captured by Alexander's men and the Indian mahouts of his allies. On the Macedonian side he records only 80 infantry killed, and 230 cavalry. 
Diodorus, though, records that 12,000 Indians fell and 9,000 taken captive, along with 80 elephants. He clicks off 700 Macedonian infantry and 280 cavalry dead. So a bit of discrepancy there from Arrian.   Peter Green's analysis is that the Macedonian casualty figure is closer to 4,000, which would have been a staggering 21% rate of the forces engaged in the battle proper. Of course, too, the dramatically high numbers of Indian casualties may be an exaggeration; nobody was counting their dead (that we have surviving records of). But even in modern warfare, actual casualty rates are rarely accurate and often exaggerated higher or lower depending on which side is reporting and what their political motivations may be. Alexander certainly had a motive to downplay the number of his own casualties to his own men and inflate those of the Indians to keep their morale up.

There is an anecdote that Porus did eventually slide off his elephant and was captured, and that Alexander had him brought to him, summoning Indian doctors to administer to the tall, wounded king. Alexander was so moved by Porus' bravery that he wanted to honor him. He asked Porus how he expected to be treated and the raja only said, "Like a king." So Alexander honored this request and not only let him keep his kingdom, but subsequently gave him a ton of money and enlisted him as an ally to guard his empire against the east. 

Of course, the Macedonian was very conscious of his image and his chroniclers were unctuous in describing his chivalry to fallen adversaries (like the charity with which he had treated the female members of Darius' family after the Battle of Issus). But the king certainly didn't act very chivalrous with most of his enemies, whom, when he defeated them in battle or captured their cities, just slaughtered them along with all their male subjects, enslaving their women and children, and often just massacring them too. His treatment of Gaza and Tyre six years earlier was war-crime level (poor Gaza, can't get a break in five thousand years!). I know he liked to think of himself as a noble, enlightened kind of king, one bringing the more civilized Greek culture to the barbarian East, one who would be admired down through history. He certainly let his fawning PR hacks promote that propaganda. But he really was no different from any other conqueror right up to this day; a ruthless, bloodthirsty, genocidal maniac. 
After his "victory" at the Jhelum, he continued his campaign eastward for another month, clear to the Beas River in modern Punjab, India, slaughtering locals and capturing fortified towns. But he couldn't trust his army to follow him farther east. But his army had had enough. They refused to follow him farther. Once they got a sight of the Himalayas in the distance, and the endless plain of the Ganges before them, and heard rumors of hundreds of thousands of Indian warriors and 6,000 elephants, they told him, in effect, that if he wanted to reach the eastern edge of the world, he could go by himself and send them a selfie.
So he decided to take his army home (well, at least to Babylon). In November, after the monsoon season had ended and his army had built a vast fleet of some 1,800 vessels, he started his retreat (though he probably said, "Retreat, Hell! I'm just attacking in another direction!" with honors to Marine Gen. O.P.Smith) but not in the direction from which they had come. Instead they floated and marched down the Jhelum to the Chenab and eventually to the Indus until they reached the Indian Ocean. Along the way they kept running into more Indian tribes, having to battle or terrify them into submission. In one of these sieges Alexander sustained the most serious wound in his short, yet puncture-riddled life. He nearly died of it and it took weeks to recover. It probably ended up shortening his life in the end; he died three years later from a terminal hangover in bed at the ripe age of 33.
And when he finally began his march/voyage down the Jhelum to the Indus and the Indian Ocean, he spent months subjugating, terrorizing, and slaughtering more of the inhabitants. These people didn't see the Greeks as civilizing missionaries, gifting them with their enlightened civilization, but as pagan, uncouth barbarians. India already had a well-established, sophisticated civilization, thank you very much; one that had thrived for thousands of years. This eastern part of the Persian Empire had always been contentious even under the Achaemenids. And the Indians regarded their resistance as a religious crusade, something that the Persians, in the western part of their empire, with their more universally tolerant Zoroastrian religion, didn't invoke.  Zealous religion never leads to peace. Ever. 

The telling thing is that, less than twenty-five years after Alexanders' conquest, after his founding of countless towns named "Alexandria" in India, after his colonizing the whole region with his soldiers and hand-picked satraps, not a single Macedonian was left alive there. Porus himself, the beneficiary of Alexander's chivalry and munificence, allied himself with Chandragupta Maurya to help found the great Maurya Empire across India (but that's possible the subject of another Obscure Battle post)

My alternate theory about this battle
This battle (Hydaspes in Greek) is historically cited as Alexander's most close-run victory, with Porus giving him a fight he had not experienced before. It undoubtedly was a very desperate battle, and not a sure thing as he went into it. But the wide recorded difference in relative casualties should be taken with a truckload of salt; probably contemporary propaganda to highlight the Macedonian's irresistible fighting prowess.
It is also suspicious that Alexander would've been so generous, even solicitous of Porus, after such a decisive a victory if he had annihilated his army as he was said to have done. I'll allow that this could've been an act of smart diplomacy in order to shore up the eastern edge of his newly-won empire with a grateful adversary-turned-ally (as the United States did with Japan and Germany after WWII). But it also could have been a smoke-screen of rationalization. 
I submit that the battle on the Jhelum may have actually been a stand-off, with neither side winning the battle, and Porus retreating with a diminished but intact force, much as Robert E.Lee had done after his "defeat" at Antietam in 1862. The fact that shortly after the battle, Alexander faced a threat of mutiny by his own Macedonians, who wanted to go home, may have had more to do with his reaching an accommodation with Porus than his touted chivalry in honoring a worthy foe. This may have been the cover story. 
Alexander's long dream had been to keep marching east until he reached the world encircling Ocean. He must have known by this time that there was far more to conquer; he hadn't really got that far into the Indian subcontinent. And he must have learned from the monarchs and new friends he had made in this part of the world of all the lands and peoples beyond this western frontier of India. By the time the army had reached Gurdaspur, 155 miles east of the Jhelum, the easternmost point of their 17,000 mile journey, they could see the awesome wall of the Himalayas in the distance, and how the plains of India just kept going on and on. The troops and their officers realized there would be no end to this; they were nowhere near the end of the world, or Ocean. And there were reports that beyond the Ganges [sic. Plutarch mistakes the Beas with that river] , there was an incomprehensibly massive army under one  Androcottus (Chandragupta Maurya) of hundreds of thousands of men, with as many as 6,000 elephants.  Moreover, if Peter Green's estimate that the true casualty cost to the Macedonians at that battle was 21% of their effective force, it is another argument in favor of Alexander reaching his limit, and the limit of his troops' trust in him.
To sum up, my theory is that Alexander didn't win this last big battle at the Jhelum (the Hydaspes), in spite of the propaganda that has filtered down for 2,350 years. It was probably a draw. And ultimately, it turned out to be a strategic defeat, signalling to all the other rajas in India that they could beat this guy. 

I know, you beg to differ.

Wargaming Jhelum
This battle (Hydaspes in Greek) has a number of interesting scenario possibilities to wargame. Since it was always recognized as Alexander's most difficult battle, that in itself suggests a great what-if. Here are some variants to test:

1. What if Alexander had delayed his crossing of the river until the monsoon was over (say in August)? He might have had to contend with an even larger enemy force as Porus' erstwhile ally, Abisares the Raja of Kashmir, came down to reinforce the Pauravas. But by that time reinforcements from Greece and Babylon would have also arrived (30,000 infantry and 6,000 cavalry, according to Green), strengthening both armies. Also the tactical considerations of an unfordable river, muddy ground, and miserable conditions of fighting in continuous rain would have evaporated (literally). 

2. What if Alexander had planned for a more efficient crossing of the Jhelum around the Admana Island to land on the actual south bank instead of the surprise, second island, thereby saving hours?

3. What if Porus had been more aggressive in sending a stronger force (including some elephants) up to the Admana crossing earlier?

4. What if Porus had used his more nimble and numerous infantry to outflank the Macedonian phalanx and attack them from the rear? He would have left enough in the center to support the elephants, but he certainly could have spared a flanking force of fifteen thousand or so to sweep southeast, around through the scrub forest. 

5. What if Porus had used all or at least some of his elephants more aggressively, charging into the Macedonian cavalry who were already terrified of getting anywhere near these monsters?

Combat Considerations
 Obviously, the two cultures had very different tactics and capabilities to take into account during a wargame of this battle. And rules should conform to those. For details on the formations of Macedonians I refer to my section on that (with graphics) in my previous post on the Granicus.

Macedonian Phalanx Infantry fought in tight formations with unapproachable front (by man or beast). They were also trained to change formation and front quickly. It should also be rated as the very highest in combat efficiency.
Macedonian heavy and light cavalry (Danae, Scythians, Bactrians, Sogdanians) should also be rated higher in CE than Indian cavalry. 

Indian infantry were not a bunch of drafted peasants, but were more-or-less experienced and professional warriors, so should be also rated high in CE and morale. But they were not trained to fight in dense columns with pikes.
Indian chariots were pretty much useless in this wet weather, even thought the ground was supposedly not as muddy.  
Elephants need special rules. Hellenic cavalry should not be able to approach them (or come within javelin range), but Indian cavalry can shelter behind them. In close combat they should be rated very high (I'd leave it to your individual algorithm to determine how high). But they should also have vulnerable morale, and likely turn on their own side in a retreat. They are also vulnerable to light infantry attack and will not charge into the front of tight Macedonian phalanx. 
The death of either leader (Porus or Alexander) should be a risk, since both fought in the thick of it. Should this happen, morale throws for every unit in that army (or overall) should be taken to see if they run. 

Weather Considerations
 Since it rained heavily rules about movement and tactics should be taken into account:

Movement; Galloping and running is out. Chariots get stuck in the mud (roll for each unit of these before moving them). For campaign scale games, I'd halve all normal movement cross country.

Archery: Indian archers, due to the nature of their bows, are not as effective as Greek and Steppe cavalry archers with their composite bows.

Visibility: Because it was raining, and the landscape was covered in scrub forest, visibility should be restricted. I'd recommend 1,000 yards.

Arrian, James Romm (ed) The Landmark Arrian: The Campaigns of Alexander,  2012, Anchor Books, ISBN 978-1-4000-7967-4

Connolly, Peter, Greece and Rome at War, 1998, Greenhill Books, ISBN 1-85367-303-X
Dodge, Theodore Ayrault, Great Captains: Alexander, 1890, Houghton Mifflin, Cambridge, MA,

Fuller, J.F.C, The Generalship of Alexander the Great, 1960, Da Capo Press, ISBN 0-306-81330-0

Green, Peter, Alexander of Macedon 356-323 BC, 2013, University of California Press, ISBN 978-0-520-27586-7