What should Hannibal have done after Cannae?

[Monopolist]

One of the main criticisms of Hannibal's strategy in the Second Punic War is that he didn't choose to march on Rome after winning his greatest victory at Cannae, decimating a Roman army of 80,000 men. According to Livy, Hannibal's lieutenant Maharbal was in strong disagreement to Hannibal's decision to rest after the battle:

Meanwhile the victorious Hannibal was surrounded by his officers offering their congratulations and urging him to take some rest during the remainder of the day and the ensuing night, and to allow his tired troops to do the same; Maharbal, however, the commander of his cavalry, was convinced there was not a moment to be lost. "Sir," he said, "if you want to know the true significance of this battle, let me tell you that within five days you will take your dinner, in triumph, on the Capitol. I will go first with my horsemen. The first knowledge of our coming will be the sight of us at the gates of Rome. You have but to follow."

To Hannibal this seemed too sanguine a hope, a project too great to be, in the circumstances, wholly conceivable. "I commend your zeal," he said to Maharbal, "but I need time to weight the plan you propose." "Assuredly," Maharbal replied, "no one man has been blessed with all God's gifts. You know, Hannibal, how to win a fight; you do not know how to use your victory."

It is generally believed that that day's delay was the salvation of the City and the Empire.

In my opinion, Hannibal made the right decision to not march on Rome. His army immediately following Cannae was too weak to threaten Rome itself, and if Hannibal failed to convince the Romans to surrender after the battle, I doubt that they would surrender days later to a bloodied, tired army at half capacity that was hurried to the gates in order to provoke fear. (Delbruck estimates that Hannibal would only have been able to get 25,000 men, about half the army that fought at Cannae, to Rome so quickly, a number which he believes and I agree would not have scared the Romans into submitting.) Nor do I think it would be a good idea for him to try and actually besiege Rome with such an army; he would need a much larger army and secure supply lines to have much of a chance of that succeeding against what would be the most well-fortified city in Italy, and that's before considering that the Romans would probably try and recall its many legions that it had sent overseas to try and repel Hannibal. I would say that the strategy of trying to win over the Italian allies and trying to gain a port from which reinforcements could be sent from Carthage was the safer plan and the plan far more likely to work.

But, what do you guys think? Was Hannibal right to do what he did IOTL? Should Hannibal have marched on Rome immediately after Cannae, even at half strength to try and scare it into submitting? Or should Hannibal have tried to besiege Rome, by building siege weapons outside the walls or counting on treachery to get the army inside?

 

[Avitus]

I don't know that I agree with you about Rome being so fearless. 25,000 men is still a lot, and more importantly they are led by a legend who has just slaughtered the best Rome has to offer in numbers that are frankly unheard of, and the rest of his army will be following behind just as soon as they are able.

Even so, Rome managed to win in the end because they vigorously recruited yet another army. Besieged they can't do that, period. Their control of their allies and vassals is slipping, and very near to breaking entirely once the news of Cannae makes the rounds. If that news is immediately followed by the news that Rome itself is under siege, you can expect even more allies to abandon Rome and join Carthage. Even if Hannibal is ultimately forced to abandon the siege for some reason he still does greater damage than he did IOTL by preventing the Romans from recruiting and causing further doubt among their allies.

 

[ray243]

I don't know that I agree with you about Rome being so fearless. 25,000 men is still a lot, and more importantly they are led by a legend who has just slaughtered the best Rome has to offer in numbers that are frankly unheard of, and the rest of his army will be following behind just as soon as they are able.

Armies, especially ancient armies cannot simply march a few hundred miles right after a battle. It's not as if Rome was only a 1-2 days march away from Cannae. Modern armies are only able to march at about 4 miles per hour, so even if we assume that the Carthaginian army can double the pace and march at 8 miles per hour without stopping, that will still take them a month to reach Rome.

By the time they reach Rome, your army is starved and fatigue because you did not allow them to rest. As such, all the Romans need to do is to meet the exhausted Carthaginian army in battle and even Hannibal cannot do anything about that.

You have to remember that the soldiers in the past were not some super-soldiers or robots you command in video games. You have to take into account of their morale and energy levels.


@Monopolist:

I think this article does highlight some of your main points regarding whether it is possible for Hannibal to march onto Rome.

http://www.jstor.org/discover/10.2307/4436417?uid=3738992&uid=2&uid=4&sid=21103685316383

 

[Mongo]

If Hannibal could have known that taking the course of action he took in OTL would eventually fail, I am sure that he would be likely to throw the dice with a siege of Rome. But he didn't know that.

With only the information he actually had at the time, I still think that he chose the correct plan of action. It didn't work in the end, of course, but I believe that his a priori chances of ultimately defeating Rome were maximized by doing what he actually did. Perhaps in a hundred universes that diverged following his decision not to besiege Rome, he ends up defeating it 40 times, compared to 20 out of 100 times when he does decide to besiege the city (his odds of success were always not very good).

 

[SlyDessertFox]

Armies, especially ancient armies cannot simply march a few hundred miles right after a battle. It's not as if Rome was only a 1-2 days march away from Cannae. Modern armies are only able to march at about 4 miles per hour, so even if we assume that the Carthaginian army can double the pace and march at 8 miles per hour without stopping, that will still take them a month to reach Rome.

What? It's 230 miles from Cannae to Rome. Assuming they marched 10 hours a day at 4 mph, thats 40 miles per day. It would take them around 6 days to reach Rome. Even if they marched for only 8 hours a day, it would take 13-14 days to reach Rome.


Anyway, I agree with Monopolist. Hannibal made the right decision that was consistent with his strategy. I think though the most important point in the war was the Metaurus. If Hasdrubal had managed to defeat the Roman army there and then Hannibal defeats the smaller Roman force in front of him, then I think ROme's on its last legs. The Latin allies were already starting to refuse to send troops to fight in the legions, partially because they had almost nobody left to send.

 

[phil03]

In my opinion, Hannibal made the right decision to not march on Rome. His army immediately following Cannae was too weak to threaten Rome itself, and if Hannibal failed to convince the Romans to surrender after the battle, I doubt that they would surrender days later to a bloodied, tired army at half capacity that was hurried to the gates in order to provoke fear. (Delbruck estimates that Hannibal would only have been able to get 25,000 men, about half the army that fought at Cannae, to Rome so quickly, a number which he believes and I agree would not have scared the Romans into submitting.) Nor do I think it would be a good idea for him to try and actually besiege Rome with such an army; he would need a much larger army and secure supply lines to have much of a chance of that succeeding against what would be the most well-fortified city in Italy, and that's before considering that the Romans would probably try and recall its many legions that it had sent overseas to try and repel Hannibal. I would say that the strategy of trying to win over the Italian allies and trying to gain a port from which reinforcements could be sent from Carthage was the safer plan and the plan far more likely to work.

I think that will be about right if everyone, as everyone seem to think, will act rationaly, witch is quite rare in the immediat aftermath of a great disaster. Sure, if Rome organize itself well they will have been able to withstand a siege but, if the ancient chronicles are any indications, the city was basically shelshocked for a while after. Of course, with time, they overcome that and fighted on but if Hannibal walked on Rome fast enough chance are that it will have fallen by itself.

 

[Monopolist]

I don't know that I agree with you about Rome being so fearless. 25,000 men is still a lot, and more importantly they are led by a legend who has just slaughtered the best Rome has to offer in numbers that are frankly unheard of, and the rest of his army will be following behind just as soon as they are able.

Even so, Rome managed to win in the end because they vigorously recruited yet another army. Besieged they can't do that, period. Their control of their allies and vassals is slipping, and very near to breaking entirely once the news of Cannae makes the rounds. If that news is immediately followed by the news that Rome itself is under siege, you can expect even more allies to abandon Rome and join Carthage. Even if Hannibal is ultimately forced to abandon the siege for some reason he still does greater damage than he did IOTL by preventing the Romans from recruiting and causing further doubt among their allies.

A good point, that besieging Rome would prevent the Romans from raising another army, and that besieging Rome might make more allies come to Hannibal than they would have otherwise. However, there are still ten untouched legions under Roman control, many of which that are not far from Rome by sea. A combination of them could relieve the capital either by attacking Hannibal at the gates or by forcing him to withdraw. In addition I'd have to say Hannibal can't allow himself to be defeated at the gates of Rome, whether it's by Roman armies or by food. (and food would be an issue, it's a long siege with a large army in unfriendly territory) It's more important for him to not be defeated than the Romans; he can lose his newly gained allies, and the morale blow in his own army would be bad if he was forced to withdraw. And as ray243 points out the army would be in bad shape anyways because they were force-marched right after the battle to get to Rome, they'd be hungry and wounded, and many more would likely die after the battle than IOTL, which would obviously weaken his army significantly in the long-term. So I think overall the risk is too great.

Armies, especially ancient armies cannot simply march a few hundred miles right after a battle. It's not as if Rome was only a 1-2 days march away from Cannae. Modern armies are only able to march at about 4 miles per hour, so even if we assume that the Carthaginian army can double the pace and march at 8 miles per hour without stopping, that will still take them a month to reach Rome.

By the time they reach Rome, your army is starved and fatigue because you did not allow them to rest. As such, all the Romans need to do is to meet the exhausted Carthaginian army in battle and even Hannibal cannot do anything about that.

You have to remember that the soldiers in the past were not some super-soldiers or robots you command in video games. You have to take into account of their morale and energy levels.

I agree with the general point, however, I can't agree that it'd take a month for Hannibal to get there. An army doesn't only march an hour a day. This is a different army, but Alexander the Great's army was well-documented at traveling at a much higher rate than that, usually between fifteen and twenty miles per day and sometimes much more than that, even over thirty miles per day. Hannibal's wouldn't be much different I expect (although the professionalism and homogeneity of the army might have aided Alexander's army's speed compared to Hannibal's large variety of ethnicities and languages to control).

@Monopolist:

I think this article does highlight some of your main points regarding whether it is possible for Hannibal to march onto Rome.

http://www.jstor.org/discover/10.2307/4436417?uid=3738992&uid=2&uid=4&sid=21103685316383

I unfortunately can't read that article; at least, I'm not willing to pay money for it. Could you summarize please.

If Hannibal could have known that taking the course of action he took in OTL would eventually fail, I am sure that he would be likely to throw the dice with a siege of Rome. But he didn't know that.

With only the information he actually had at the time, I still think that he chose the correct plan of action. It didn't work in the end, of course, but I believe that his a priori chances of ultimately defeating Rome were maximized by doing what he actually did. Perhaps in a hundred universes that diverged following his decision not to besiege Rome, he ends up defeating it 40 times, compared to 20 out of 100 times when he does decide to besiege the city (his odds of success were always not very good).

Honestly the odds were probably even lower than that (for both). Even with Hannibal's genius the war was stacked against him throughout.

In hindsight who knows, maybe marching on Rome would have been enough. But from Hannibal's perspective I think he made the right call.

I think that will be about right if everyone, as everyone seem to think, will act rationaly, witch is quite rare in the immediat aftermath of a great disaster. Sure, if Rome organize itself well they will have been able to withstand a siege but, if the ancient chronicles are any indications, the city was basically shelshocked for a while after. Of course, with time, they overcome that and fighted on but if Hannibal walked on Rome fast enough chance are that it will have fallen by itself.

A fair point, that we can't expect the Romans to necessarily be rational in such a state. My feeling however is that if the Romans remained committed to the war after being defeated in the first place, that they wouldn't fall apart upon Hannibal marching with a much smaller, much more tired army, that would probably be repelled from the gates either by food or arms.

 

[Elfwine]

Rome was seriously shaken up by Cannae, but not contemplating surrender. And Hannibal does not have the forces to simply walk into the city if its defended - 25,000 men is a lot, but the number of men Rome could muster was greater. Not even all the forces it had at Cannae were eliminated, if it came to that,

So I think Hannibal knew better "how to use a victory" than his impulsive lieutenant.

 

[Jurgen Wullenwever]

But if Hannibal had supposed:
1/ that the Romans would never accept defeat,
2/ so peace would not be possible until Rome was dust,
3/ and that Carthaginian support over the sea would be scarce,
would it still be the right decision not to march on Rome?

As it was when he did not, the Romans learned how to fight Hannibal, and how to gain strategic victories, and how to win the war, while Hannibal just achieved keeping a battlefit army around in a hostile country for sixteen years - a great deed, but not a warwinning one in this case.

 

[SlyDessertFox]

As it was when he did not, the Romans learned how to fight Hannibal, and how to gain strategic victories, and how to win the war, while Hannibal just achieved keeping a battlefit army around in a hostile country for sixteen years - a great deed, but not a warwinning one in this case.

I disagree vehemently with this-his problem was that he was getting no outside support-he tried to get Phillip V but that didn't work, Carthage wasn't helping him, and Hasdrubal couldn't in Spain.

Yet he was his closest to victory in 207 right before Metaurus. So that marching around for (at that point) 11 years seemed like it actually almost payed off.

 

[Elfwine]

But if Hannibal had supposed:
1/ that the Romans would never accept defeat,
2/ so peace would not be possible until Rome was dust,
3/ and that Carthaginian support over the sea would be scarce,
would it still be the right decision not to march on Rome?

As it was when he did not, the Romans learned how to fight Hannibal, and how to gain strategic victories, and how to win the war, while Hannibal just achieved keeping a battlefit army around in a hostile country for sixteen years - a great deed, but not a warwinning one in this case.

Marching on Rome would only be the right decision if it could bring Rome to terms. Doing it while Rome still has ample resources and will to draw on for its defense would not be the right time.

 

[Seleucus]

I unfortunately can't read that article; at least, I'm not willing to pay money for it. Could you summarize please.

I can do that. The main points are:

- It's commonly assumed that Hannibal didn't have a siege-train or the capability to conduct sieges, although this is not explicitly stated by any source. The article instead argues that Hannibal had shown the capability to deploy and use siege weapons when necessary, citing primary sources (and blaming a reliance on Livy who he sees as unreliable.)

- The author estimates a realistic rate of march for Hannibal as 8-10 miles per day (citing Polybius.)

- The main port for Rome at this time was Puteoli, 120 miles south of Rome and easily cut off by siege. Thus, a navy is unnecessary to effectively siege Rome.

- As a result, the author concludes that logistical limitations were the reason for Hannibal's actions. He makes a variety of arguments to draw conclusions about the number and type of camp followers, cavalry horses, and pack-animals in Hannibal's army and concludes that an immediate attack on Rome would require more than 500,000 pack animals to carry all the necessary food (for a direct attack that doesn't stop/slow down to forage.) He argues that logistical constraints were the primary constraint to Hannibal's campaigns and in fact essentially dictated his actions until Cannae.

"Before Cannae, Hannibal's army was little more than a band of brigands, forced to wander the countryside in search of sustenance."

 

[Jurgen Wullenwever]

I disagree vehemently with this-his problem was that he was getting no outside support-he tried to get Phillip V but that didn't work, Carthage wasn't helping him, and Hasdrubal couldn't in Spain.

Yet he was his closest to victory in 207 right before Metaurus. So that marching around for (at that point) 11 years seemed like it actually almost payed off.

But was he closest to victory by himself, or together with Hasdrubal? If he was doing the right thing and therefore could manage victory without Hasdrubal, then Metaurus would not be the decisive battle it seems to have been.

What I am getting at, without any opinions although it might seem so sometimes, is that if Hannibal had supposed the above points, no help and no negociations, was he doing the right thing to win the war?

 

[Monopolist]

But if Hannibal had supposed:
1/ that the Romans would never accept defeat,
2/ so peace would not be possible until Rome was dust,
3/ and that Carthaginian support over the sea would be scarce,
would it still be the right decision not to march on Rome?

As it was when he did not, the Romans learned how to fight Hannibal, and how to gain strategic victories, and how to win the war, while Hannibal just achieved keeping a battlefit army around in a hostile country for sixteen years - a great deed, but not a warwinning one in this case.

Him making assumptions that would later prove to be correct might or might not have changed his strategy, but it doesn't change the situation at hand. Rome was still too strong to lay siege to for his army, and a march on Rome so quickly after Cannae would have been very risky and much more unlikely to work than trying to win over Rome's allies over time.

I can do that.

Thanks.

- It's commonly assumed that Hannibal didn't have a siege-train or the capability to conduct sieges, although this is not explicitly stated by any source. The article instead argues that Hannibal had shown the capability to deploy and use siege weapons when necessary, citing primary sources (and blaming a reliance on Livy who he sees as unreliable.)

Yeah, Hannibal was able to attack cities when it made sense to. You can build siege weapons on site; Hannibal surely would have had access to some engineers. So I've never bought that argument either.

- The author estimates a realistic rate of march for Hannibal as 8-10 miles per day (citing Polybius.)

I would like to see what he cites from Polybius to reach those numbers; it seems to me unrealistically slow considering the rate of march for armies around this time period.

- The main port for Rome at this time was Puteoli, 120 miles south of Rome and easily cut off by siege. Thus, a navy is unnecessary to effectively siege Rome.

I can agree with this to an extent. I think that Hannibal can work around not having a navy to besiege Rome, and though Puteoli is rather far away it would be possible to cut it off and really hurt Rome that way. But there are other ports, and it would be hard for Hannibal to plug up all the holes effectively while also keeping enough men at Rome to maintain the siege. A Punic navy would help immensely to help this problem, if only to prevent Roman armies from returning from Sicily or Sardinia or Spain to relieve Rome. Plus it would obviously help support his army logistically, if a Punic navy was present to import food and whatnot and prevent Hannibal from scouring all of Central Italy to find enough to feed a stationary army for a few months.

- As a result, the author concludes that logistical limitations were the reason for Hannibal's actions. He makes a variety of arguments to draw conclusions about the number and type of camp followers, cavalry horses, and pack-animals in Hannibal's army and concludes that an immediate attack on Rome would require more than 500,000 pack animals to carry all the necessary food (for a direct attack that doesn't stop/slow down to forage.) He argues that logistical constraints were the primary constraint to Hannibal's campaigns and in fact essentially dictated his actions until Cannae.

Seems reasonable to conclude. It would be a nightmare for Hannibal to keep the army fed. 500,000 pack animals seems an overestimation to me though, there is a tipping point where you're essentially bringing pack animals to feed your other pack animals, a point which I think the author must have had to cross. Although I suppose the point that he was trying to make is that that IS impractical, so I'd agree on that.

 

[SlyDessertFox]

But was he closest to victory by himself, or together with Hasdrubal? If he was doing the right thing and therefore could manage victory without Hasdrubal, then Metaurus would not be the decisive battle it seems to have been.

What I am getting at, without any opinions although it might seem so sometimes, is that if Hannibal had supposed the above points, no help and no negociations, was he doing the right thing to win the war?

Well alone he didn't have much of a chance at winning in Italy-His entire reasoning for continuing to march around Italy was based on the assumption that he would get help from Carthage and from Hasdrubal and that the Italian cities would revolt to his banner. He never expected that Hasdrubal was going to be fighting a war with the Romans in Spain, or that the Carthaginian government owuld be determined to send support to everyone and everywhere but Italy.

So, again, Hannibal's strategy from day 1 rested on being able to get reinforcements from Spain if he could not knock out Rome quickly. Regardless marching on Rome would only serve to put him in a bad position-Rome had other forces and Hannibal would risk being cut off and surrounded, since any siege of the city isn't going to be successful.


The Romans by the time of Metarus as I said, were also at the point of exhaustion. Their latin allies were even beginning to refuse sending troops to fight in the Roman legions IIRC. Rome was winning in Spain, sure, but Spain was irrelevant if Hannibal could win in Italy. This is simply not the case after Cannae.

 

[Seleucus]

I would like to see what he cites from Polybius to reach those numbers; it seems to me unrealistically slow considering the rate of march for armies around this time period.

He cites Polybius 3.50.1 as saying it took Hannibal's army 10 days to march 800 stades, translating into 8-10.5 miles/day (I haven't checked the sources myself.) Presumably this involves/includes foraging/etc. time.

I can agree with this to an extent. I think that Hannibal can work around not having a navy to besiege Rome, and though Puteoli is rather far away it would be possible to cut it off and really hurt Rome that way. But there are other ports, and it would be hard for Hannibal to plug up all the holes effectively while also keeping enough men at Rome to maintain the siege. A Punic navy would help immensely to help this problem, if only to prevent Roman armies from returning from Sicily or Sardinia or Spain to relieve Rome. Plus it would obviously help support his army logistically, if a Punic navy was present to import food and whatnot and prevent Hannibal from scouring all of Central Italy to find enough to feed a stationary army for a few months.

Puteoli being far away is what makes it easy to cut off. Just block the road leading to it, and you're done. Everything else remains valid though (the author portrays much of Hannibal's campaigns as being a quest to achieve a port to be supplied by that Punic navy.)

Seems reasonable to conclude. It would be a nightmare for Hannibal to keep the army fed. 500,000 pack animals seems an overestimation to me though, there is a tipping point where you're essentially bringing pack animals to feed your other pack animals, a point which I think the author must have had to cross. Although I suppose the point that he was trying to make is that that IS impractical, so I'd agree on that.

The author included that tipping point in his calculation as to the number of pack animals. He assumes a 19-day march to Rome and states from his calculations/assumptions that Hannibal being able to carry even a week's supply of provisions at a time was a rare occurrence.

 

[Grouchio]

Didn't you already do an ATL on this, Monopolist?

 

[Monopolist]

He cites Polybius 3.50.1 as saying it took Hannibal's army 10 days to march 800 stades, translating into 8-10.5 miles/day (I haven't checked the sources myself.) Presumably this involves/includes foraging/etc. time.

Must be. I would assume that the army would be made to go faster than that though to capitalize on the situation. Especially if Hannibal were to divide his army as Maharbal suggests (sending the cavalry ahead); that would help the speed and the logistical situation, although it does leave both armies more vulnerable in the time being.

Puteoli being far away is what makes it easy to cut off. Just block the road leading to it, and you're done.

True; I think I was overcomplicating it in my head.

The author included that tipping point in his calculation as to the number of pack animals. He assumes a 19-day march to Rome and states from his calculations/assumptions that Hannibal being able to carry even a week's supply of provisions at a time was a rare occurrence.

Gotchya.

Didn't you already do an ATL on this, Monopolist?

I've done a Carthage timeline, but not a Hannibal marches on Rome after Cannae timeline.

 

[ggarner57]

Where were the remaining legions after Cannae? If they were scattered throughout, could Hannibal either 1. March towards rome, and force them to come engage him, hopefully meeting the legions before they could unite.
Or 2. March to cut off Rome's port, capturing supplies there to keep his army marching, and force the nearest Romans to attack him, before reinforcements can arrive. Either one further whittles down Rome's army, and makes their allies more and more reluctant to fight.


Of course, this is assuming the Romans would march against Hannibal again after the beatings they'd suffered. I would think they would, however, if it appeared Rome itself was threatened.

 

[Dave Howery]

to get Hannibal to be able to march on Rome, I'd think you'd need an even earlier POD... he doesn't lose so many men/supplies crossing the Alps. Not sure how you get that done though...