Alexander versus Caesar

[aligern]

Justin ' that would mean having considerably more legionaries than Alex had phalangites' . Crassus invades Parthia thit, I think, 40,000 legionaries I think Pompey heads for that many at Pharsalus. I doubt that raising the numbers is a problem to Caesar.
If we ran it as a wargame then the difficulty Alex has is that his phalanx is expensive, the hypaspists are expensive and the companion cavalry are expensive. So the Romans get a quantity advantage. Caesar cut his depth twice at Pharsalus so no problem with supplying troops to the wings to bolster the Roman cavalry.

[Justin Swanton]

Justin ' that would mean having considerably more legionaries than Alex had phalangites' . Crassus invades Parthia thit, I think, 40,000 legionaries I think Pompey heads for that many at Pharsalus. I doubt that raising the numbers is a problem to Caesar.
If we ran it as a wargame then the difficulty Alex has is that his phalanx is expensive, the hypaspists are expensive and the companion cavalry are expensive. So the Romans get a quantity advantage. Caesar cut his depth twice at Pharsalus so no problem with supplying troops to the wings to bolster the Roman cavalry.

One can throw in quite a few ifs here. If Alexander went to war with Rome he would know or find out the composition and fighting style of the Roman army. He would realise the need for enough of the only infantry sufficiently well armed to overcome the legions, namely pikemen. Presuming he had already conquered the Persian empire, he would have a vast manpower reserve to draw from, and would be able to raise and train any number of phalangites. Presuming Caesar had 40 000 legionaries at his disposal, he could deploy them in only two lines each 8 men deep for a frontage of 2500 yards. Alexander, deploying 16 men deep, or 8 deep on a compact frontage, would need the same number of phalangites to match Caesar's frontage. If Caesar stretches himself any thinner his line relief system will probably fall apart - the centre of the line will be sent packing before he has time to do anything to the Macedonian flanks.

If however Alexander had only 12 000 phalangites/hypaspists at his disposal (i.e. before he completed his conquest of Persia), then the legions could overlap his phalanx and he would be obliged to pull off a tactical coup before his heavy infantry were outflanked and overwhelmed. Tactical coups were exactly the kind of thing Alex was used to doing, so everything would depend on how well Caesar knew Alex's tactical repertoire. Did he have an answer to the cavalry wedge? Could he protect himself from an attack on his person by Alex? Bearing in mind that Caesar has no quick way of winning the battle himself, since his main strength is in his infantry.

[aligern]

Which is why we should fight it on the table top! Pyrrhus was rated a good general and had great difficulty with Roman armies that were inferior to Caesar's  or were at least led by lesser men than Divine Julius. I agree that Alexander is likely better than Pyrrhus, but that Caesar is way better than the consuls that opposed the Epirote.
The troublewith Alexander's tactic of killing the oppising general is that that mghtwell nt stop the Romans. If Alexander gets lucky Julius might get caught, but meanwhile the Macedonians get chopped into small pieces.
If I was playing Caesar I'd have a few cohorts of the tenth legion and some archers by me.

Roy

[Patrick Waterson]

This is turning into more of a mobilisation contest than a comparison of generalship.  Bear in mind that once Alexander has his empire his manpower base will considerably exceed that of first century BC Rome.

So rather than engage in mutual escalation, I think we need to firm up the forces for this decisive clash, bearing in mind that we need a manageable battle and the gods need to cheat a bit on the temporal front to bring these two together.  The best way to do this would be to make it a surprise.

For example ...

Caesar thinks he is about to give battle to Pompey at Pharsalus.  He has 22,000 legionaries in 80 cohorts, six of the best of which are kept back for his little surprise move.  He also has 1,000 cavalry with 1,000 pillion-riding friends.

Alexander thinks he is approaching the Persian forces at the Granicus.  Of his 30,000 infantry and 5,000 cavalry he has the cavalry, the hypaspists, the Agrianes, the archers and the phalanx.  This gives him about 12,000 heavy and 2,000 light infantry with his 5,000 cavalry.  His Greek and Thracian infantry have not yet come up - if we want to be fussy about conferring equal numbers, we can allow 5,000 of them to turn up part-way through the fighting.  If not, we can leave them out of this day's action.

Whose terrain do we use?  Caesar is covering only one flank with cavalry, so we might as well use the Pharsalus terrain.  Alex will realise he is in a strange location when his army mysteriously reappears on the lower slopes of the elevation that holds - or held - Pompey's camp, but there is no particular reason for him to redeploy.

Now for deployment and frontages: Caesar's 22,000 infantry, less his 3,000-man special strike force, leaves 19,000 infantry in three lines.  As his units are understrength, he might not use the full depth for each line; furthermore he may well deploy 4-4-2, which in plain English means four cohorts in each legion's first and second lines but only two (half depth) in the third.

If he deploys his lines 8 deep - 8 deep - 4 deep (the third line at half depth because half strength - 2 cohorts) he would have an infantry frontage of 950 yards.  This is sufficiently close to the 800 yards of a traditional double consular army to seem not unreasonable.

His cavalry, if deployed five deep (half the usual ten deep) would have a frontage of a further 400 yards.

Alexander would have his cavalry and accompanying missilemen on the right, 1,800 Companions plus Paeonians and the Prodromoi, say 2,700 cavalry, 500 archers and 1,000 Agrianes.  The other 500 archers might be here or on the opposite flank.  Assume a frontage of about 300 yards for these, the missile troops preceding and intermingling with the cavalry squadrons.

The hypaspists and phalangites would be 8 deep but dense (18" frontage per man).  This would give them a frontage of 750 yards.

Parmenio's wing would have the Thessalians (1,800?) plus allied Greek and Thracian cavalry, say 2,300 cavalry, plus maybe 500 archers.  Assume a frontage of about 250 yards.

Caesar's frontage comes to 1,300 yards.  Alexander's works out at around 1,300 yards - a useful coincidence.

The battle will hinge on a number of points.

1) Can Alexander's cavalry ride through/ride down Antony's legionaries on Caesar's left? (Favoured opinion: yes - legionaries did not shine against lance-armed cavalry)

2) How will Caesar's legionaries under Gnaeus Domitius and Sulla cope with the hypaspists and phalagites? (Favoured opinion: badly - legionaries never broke a phalanx frontally without help)

3) Will Caesar's six-cohort ambush work against Parmenio's cavalry wing? (Favoured opinion: probably - Parmenio was cautious but also unimaginative)

So I think Alexander would win this one, despite pleas for help from Parmenio on the left ...

Pyrrhus was rated a good general ...

I have increasing difficulty seeing why.  Given his fairly consistent record of near-success, I think he was more respected for his knowledge of the military art than his application of it, and for his "daring and prowess" in combat rather than his ability to clear the field of the enemy.  See Plutarch's Pyrrhus chapter 7 for how he made his reputation.  Also:

"This conflict did not fill the Macedonians with wrath and hate towards Pyrrhus for their losses, rather it led those who beheld his exploits and engaged him in the battle to esteem him highly and admire his bravery and talk much about him. For they likened his aspect and his swiftness and all his motions to those of the great Alexander, and thought they saw in him shadows, as it were, and imitations of that leader's impetuosity and might in conflicts. The other kings, they said, represented Alexander with their purple robes, their body-guards, the inclination of their necks, and their louder tones in conversation; but Pyrrhus, and Pyrrhus alone, in arms and action.

[2] Of his knowledge and ability in the field of military tactics and leadership one may get proofs from the writings on these subjects which he left. It is said also that Antigonus, when asked who was the best general, replied, 'Pyrrhus, if he lives to be old.' "

He did not live to be old.

[aligern]

Lets disagree first on the mobilisation. You pick a battle (Pharsalus) in which Caesar has a much reduced army and is fighting a civil war. Its wrong to say that Alexander' s Empire has greater resources than the Roman Empire in 50 BC because, in the crucial area of  heavy infantry Macedon's resources are less than those of the Romans...probably 20 per cent . In terms of good cavalry the Macedonians have the advantage in quality at the top end, but the Romans can probably deliver as many cavalry to the battlefield as Alexander and that will hold his strike orce in play. The real advantage that the Romans have is their infantry because, as said earlier, they are one of the few infantries that can fall back in front of the phalanx. That liberates the legions on the flank of the phalanx to fall upon it where it cannot turn and is likely decisive.
The point that Patrick and Justin have not dealt with is Caesar's potential use of field fortifications, a branch of the military art in which Rome far exceeded Macedon. Caesar can pick and choose his ground and not  give battle unit it suits him. He won't be refighting Pharsalus, but a new battle with , potentially, the odds in his favour. Again,Ihe can use trenches as Sulla did, to hinder the ability of the Macedonian cavalry to stretch his front and turn a flank to create a gap.
Alexander is easily conceptualised as a military genius because he was universally victorious through being aggressive, but he generally fought weaker opponents. The Persians were numerous but disorganised, the Greeks lacked a unified command and Alexander's father had designed the Macedonian army to beat Greeks. The Indians have a record of losing pretty consistently to invaders from the North West, be they Alexander,, the Greek Successor Staes, Parthia, the Saka, the Kushans etc. Alexander beats all these opponents through guile and agression, but with Rome he would meet an immovable object against an ordinary Roman general, more than his match if he met Caesar who is also inventive.
So in my putative reconstruction Caesar forms in two lines a total of 12 deep with say 24,000 men . That gives him a frontage of 2000 yards . He then has a third line of 4000 men to stiffen the flank(s) .
One immense advantage that Rome has the ability of the legions facing the phalanx to fall back in front of it and hence the possibility of allowing the phalanx to move firward until it cracks. If necessary Caesar could retreat into rough ground, allow the phalanx to. crack up and then insert cohorts into the gaps. I doubt that Aleander's force can cope with this. It is Polybius who describes this fatal weakness of the phalanx and I submit he knew rather better than we do how the different systems performed. His assessment of the phalanx is that it will always fail because of its inherent weaknesses against a Roman system.
Roy

[Mark G]

I tend to think that the big Macedonian advantage was using combined arms against opponents who isolated each troop type they had from each other.

The romans by Caesars time did not have that problem, and a much better ability to mobilise new armies quickly

[Jim Webster]

The Romans of Caesar's time also had the ability to mobilise new generals rapidly. Given that the Parthians had Roman allies and Roman infantry in their army, I suspect Alexander could have guarded the flanks of his phalanx with legionaries 

Jim

[aligern]

Then, Jim, to be fair to both they can each design the perfect army and bring it to the battle. So both can have cataphracts and horse archers and pikes or legionaries.
Mind you I bet Caesar would not be choosing any pikemen.
Roy

[Jim Webster]

Then, Jim, to be fair to both they can each design the perfect army and bring it to the battle. So both can have cataphracts and horse archers and pikes or legionaries.
Mind you I bet Caesar would not be choosing any pikemen.
Roy

Be a beggar if they both turned up with Parthian armies then, on the grounds that they managed to defeat both pike armies AND legionary armies 

Jim

[Patrick Waterson]

Lets disagree first on the mobilisation. You pick a battle (Pharsalus) in which Caesar has a much reduced army and is fighting a civil war. Its wrong to say that Alexander' s Empire has greater resources than the Roman Empire in 50 BC because, in the crucial area of  heavy infantry Macedon's resources are less than those of the Romans...probably 20 per cent . In terms of good cavalry the Macedonians have the advantage in quality at the top end, but the Romans can probably deliver as many cavalry to the battlefield as Alexander and that will hold his strike orce in play.

Taking the armies from Pharsalus and the Granicus is a way of giving each side a similar 'points value' so the main variable is the skill of the C-in-C.  The point is to avoid precisely this auction of imagination in favour of one's preferred candidate.

If we are to instead take each general at the height of his power and resources, I think we would have to look at cavalry mobilisation figures for the respective empires.  If Alex wanted to maximise cavalry, he would have no trouble matching the 40,000 or so fielded by Darius at Gaugamela - of these, perhaps 10,000 would be Macedonian, Thracian, Thessalian and Greek and the rest Persian, Bactrian and Scythian.

If I remember correctly, the Roman Republic never massed more than around 7,000 cavalry on any given battlefield.  Caesar might be able to improve considerably on this by drawing upon the resources of Gaul and Numidia, but what would his upper limit be?  We start having to look at logistical organisation, a department in which Alexander's empire would have superiority on account of its higher population, superior concentration of major cities, Persian administrative arrangements and superior maritime resources.

The real advantage that the Romans have is their infantry because, as said earlier, they are one of the few infantries that can fall back in front of the phalanx. That liberates the legions on the flank of the phalanx to fall upon it where it cannot turn and is likely decisive.

Not really - at Cynoscephalae and Pydna they do not 'fall back'; they are bundled back involuntarily.  This can have only one ending unless the phalanx is attacked by someone else from somewhere else, which Alexander would take care not to allow.

The point that Patrick and Justin have not dealt with is Caesar's potential use of field fortifications, a branch of the military art in which Rome far exceeded Macedon. Caesar can pick and choose his ground and not  give battle unit it suits him. He won't be refighting Pharsalus, but a new battle with , potentially, the odds in his favour. Again,Ihe can use trenches as Sulla did, to hinder the ability of the Macedonian cavalry to stretch his front and turn a flank to create a gap.

But how much of an advantage would this confer?  Caesar in Spain showed how to deal with field fortifications: you just cut off the enemy's supplies and avoid battle.  I cannot see this being an insuperable problem for Alexander.  If Caesar has tucked himself into a handy corner so that his supplies are somehow inviolate, Alexander gets to play with his artillery.

Alexander is easily conceptualised as a military genius because he was universally victorious through being aggressive, but he generally fought weaker opponents. The Persians were numerous but disorganised, the Greeks lacked a unified command and Alexander's father had designed the Macedonian army to beat Greeks. The Indians have a record of losing pretty consistently to invaders from the North West, be they Alexander,, the Greek Successor Staes, Parthia, the Saka, the Kushans etc. Alexander beats all these opponents through guile and agression, but with Rome he would meet an immovable object against an ordinary Roman general, more than his match if he met Caesar who is also inventive.

This seems to me to be a declaration of faith rather than fact.  Alexander won consistently and economically because he made very sure that he knew how his opponents functioned and what their weaknesses were.  Had he come up against the Romans, one can be sure that Polybius' famous observation about cavalry would have partly altered to:

"It was to cavalry that *Macedon* owed its victories and Rome its defeats."

So in my putative reconstruction Caesar forms in two lines a total of 12 deep with say 24,000 men . That gives him a frontage of 2000 yards . He then has a third line of 4000 men to stiffen the flank(s) .

Alexander, with a smile, would field a Hydaspes-type deployment, lop off one of the over-extended Roman flanks and roll up the rest of the line.

One immense advantage that Rome has the ability of the legions facing the phalanx to fall back in front of it and hence the possibility of allowing the phalanx to move firward until it cracks.

Alas no, as mentioned.

If necessary Caesar could retreat into rough ground, allow the phalanx to. crack up and then insert cohorts into the gaps. I doubt that Aleander's force can cope with this.

This is a sensible recourse to avoid defeat, although Alexander would have more sense than to commit a phalanx on rough ground.

It is Polybius who describes this fatal weakness of the phalanx and I submit he knew rather better than we do how the different systems performed. His assessment of the phalanx is that it will always fail because of its inherent weaknesses against a Roman system.

But he also points out that on level ground the legion has no chance, and he specifically does not mention it as having the ability to disorganise a phalanx by falling back, or even being able to fall back intact, for that matter.  His main point is that the Roman system keeps a lot of troops 'in reserve' to take advantage of developments whereas the Macedonian system of his day (as opposed to Alexander's) put all its eggs in one phalangite-line basket.

As pointed out earlier, Alexander customarily maintained a second line of more flexible troops which could deal with opponents who sought to exploit any gaps that did develop in the phalanx for any reason.

[Mark G]

It is all a bit too deterministic, pat.

Alexander gets to act dynamically, Caesar stands there and lets him do it.

Personally, I don't rate Caesar highly, and am baffled by folk who do, but one thing I certainly would credit him with is an ability to react quickly and decisively to a new threat.

In a straight fight, I would expect him to pull out of level ground, and then tempt Alex to come in at him.
And I would expect Alex to fall for it.

[Patrick Waterson]

True, Mark, we do need to give Caesar his due - he was usually good at reacting to being surprised (cynics say he needed to be, the number of times he was surprised).

If Caesar adopted an extended line deployment as Roy proposed (which I do not see Julius doing, personally) then we would leave himself vulnerable to a dynamic approach by Alexander which switched to envelop and crush one wing.  This is one reason why wide frontages were not particularly popular in the classical period: if your opponent could manoeuvre at all well, you would leave yourself open to this kind of thing.

Caesar might try to tempt Alex on to difficult terrain, but I do not see Alex falling for that one: on the first day at Gaugamela, he marched to give battle, saw the way the Persians were drawn up, cancelled the battle and spent the day reconnoitring the Persian positions.  The following day he gave battle - with a plan that collapsed the Persian army like a pricked balloon by taking advantage of the ramifications of its deployment.

So if JC set up with difficult terrain behind so he could fall back onto it, I would expect Alex to punch through both Roman wings with his cavalry followed by his second-line troops (good rough terrain types like peltasts for the most part) and gift-wrap the Romans while his phalanx was still advancing.  Caesar would then have to cut his way through to the difficult terrain under pressure and surrounded - and Alexander's army was a far more potent opponent than the Numidians at Ruspina, whom Caesar did manage to break free of when surrounded.

Part of the problem is that the Roman military system as under Caesar while good enough to beat almost anyone else, does not seem quite up to handling a Macedonian (or Macedonian Imperial) army in its prime.  What would have been interesting is to see how Caesar would have handled the Parthians had he lived - I have a few ideas about that, which may or may not be what he had in mind.

[aligern]

Mark is absolutely right Patrick, your infatuation with Alexander leads you to ignore the other side on the field. If Caesar extends then Alexander withdraws a flank a la Hydaspes then Alex is not facing Indians with a  clunky command system, the Roman flank will be round on his flank quicker than you can say Hephaistion  and certainly quicker than I can spell it!


Roman armies deploy active and mobile reserves which I do not think Alexander does, so any penetration will be met by fresh troops.

Caesar beats Pompey who is well regarded, who does Alexander beat who has an army or a general to be feared.
Alexander gets strategically surprised by Darius at Issus so please let us not fall into the trap of believing that Caesar is the only one that takes risks.  Of course Caesar's risky behaviour may be in conscious imitation of Alexander (pace Lendon Soldiers and Ghosts) .

Against Parthians I'd expect Caesar to take advice and stick to the high ground, then march down Tigris or Euphrates building forts as he went. At the same time, if politically possible he would organise an Armenian penetration from the North to split the Parthian forces.
Even Crassus would have survived with most of his army intact if his nerve had not failed him.
Roy

[Patrick Waterson]

Mark is absolutely right Patrick, your infatuation with Alexander leads you to ignore the other side on the field. If Caesar extends then Alexander withdraws a flank a la Hydaspes then Alex is not facing Indians with a  clunky command system, the Roman flank will be round on his flank quicker than you can say Hephaistion  and certainly quicker than I can spell it!

This is why at the Hydaspes and at our hypothetical Pharsalus-with-extensions Alex has a detached cavalry wing.  Any Roman force moving to flank Alex gets flanked by Task Force Coenus.

Roman armies deploy active and mobile reserves which I do not think Alexander does, so any penetration will be met by fresh troops.

This depends on what is meant by 'active and mobile reserves'.  Roman armies habitually drew up in three lines and engaged with one, which gave them adequate - and under Caesar usually more than adequate - flexibility to respond against opponents who moved at an infantry pace.  Alexander however was a genius at timing and had a substantial very high quality cavalry force, which made fighting against him a very tricky exercise (as Bessus' cavalry wing found out at Gaugamela).  An over-extended Roman wing could easily be 'punched out' before it could be relieved by troops from elsewhere along the front, especially if we consider the generally lacklustre showing of Roman infantry against lance-armed cavalry, even Seleucids and Parthians, who lacked something of the quality and skill of Alexander's Companions.

Caesar beats Pompey who is well regarded, who does Alexander beat who has an army or a general to be feared.

Caesar also beats Labienus, who is also well-regarded, not least by Caesar.  Then again, beating Pompey was well within Sertorius' capabilities even with a non-Roman army (albeit reformed along Roman lines), as he proved at the Sucro (Pompey was doubly fortunate in that his expensively-attired mount diverted his pursuers from himself while Metellus rescued Pompey's army).  Sertorius, while very good, is not considered to be in quite the same league as Caesar or Hannibal - or Scipio Africanus - let alone Alexander, but he beat Pompey during the latter's prime, not his dotage.

As for Alexander,
1) Memnon of Rhodes was considered the premier Greek general of his era, and Alexander defeated him quite handily at the Granicus. 
2) Even Darius himself had a high military reputation - at least prior to Issus. 
3) Porus was considered eminent among Indian kings.

Alexander gets strategically surprised by Darius at Issus so please let us not fall into the trap of believing that Caesar is the only one that takes risks.  Of course Caesar's risky behaviour may be in conscious imitation of Alexander (pace Lendon Soldiers and Ghosts) .

Alexander was not taking risks at Issus: the 'strategic surprise' was because he had been led to believe there was only one pass through the Taurus range (which he firmly controlled) when in fact there were two.  He seems always to have double-checked his intelligence after that (or been more fortunate with his guides).

Against Parthians I'd expect Caesar to take advice and stick to the high ground, then march down Tigris or Euphrates building forts as he went. At the same time, if politically possible he would organise an Armenian penetration from the North to split the Parthian forces.
Even Crassus would have survived with most of his army intact if his nerve had not failed him.

This is true, and Mark Antony managed a creditable fighting retreat with the odd success along the way.  But Caesar would be playing for keeps, and I think that in addition to taking the Armenia route into Media (and avoiding Mesopotamia entirely) he would be laying the groundwork among the principal Persian families for permanent removal of the Parthians.  One may note how he very consciously used Gauls against Gauls, posing as a liberator until he had enough control to put the lot under his thumb (although the resultant revolt by Vercingetorix pretty nearly ended Caesar's career) - I am sure he would have tried to pose as a liberator of the Persians from the Parthians, drawing on Persian manpower and trying to foment revolts in the hope of galling the Parthians to attack him in a situation unfavourable to themselves.  I feel he would have made extensive use of caltrops and similar anti-cavalry methods to prepare the battlefield beforehand if it came to a battle - these Great Captains rarely 'fought fair'.

So why would he not do this against Alexander?   He might well, but Alexander would not be caught - any more than he was by Darius' preparations at Gaugamela.  On the political angle, his Persians were intermarried with his Macedonians, so had a stake in the status quo that Caesar would find hard to better.  Conversely, Alexander could easily pose as the liberator of Rome - or of various peoples under the Roman thumb.  Caesar might wake up one day to find his Gauls had all left to re-enlist under Alexander as Galatians.

[aligern]

And what pray are Caesar's cavalry doing whist Coenus is suppisedly flanking the legionaries who are flanking the phalanx? Just watching? No, they will be engaging the Macedonians.
I don't know where you get this putative lacklustre performance of Roman infantry againstlance armed cavalry. Properly formed up they do just fine. At Carrhae cataphracts do not charge through them, at Pharsalus, intermingled with the Caesarian cavalry they drive off Hellenistic cavalry.


The answer is for several groups to try this one on the tabletop.