Roman Rules for War - How to conquer an Empire

A typical Roman imperial army on its way to battle was a formidable force. The main reason for this was the amount of time and resources that were allocated to preparation before a campaign, which was the very first rule of war the Romans followed whenever possible. Vegetius tells us that before marching out, a general was expected to carefully study maps of the region, which were put together by different trustworthy locals who were familiar Then, each of their reports and maps were compared for similarities. If there were any uncertainties, Roman generals were known to change their routes with the help of proper guides, who were promised a good reward for their service. And all of the army's routes were kept hidden, even from the soldiers themselves. Julius Caesar in Gaul was famous for using a large network of informants to gather the latest rumors across the Gallic tribes around him. Pre-battle preparation also extended to military training. The least experienced soldiers in any Roman army spent the last four months performing rigorous physical activities and sparring twice a day, while the most experienced soldiers have been doing this for up to 25 years. This repetitive training was harsh, but will make them more contempt and composed in the battle to come. It is as Josephus wrote about the Romans, their exercises are bloodless battles, and their battles bloody exercises. The level of attention given to training was equaled or even surpassed when it came to logistics. A Roman general would spend most of his time addressing the logistical situation with his staff, and making careful calculations and necessary arrangements with local communities for quality supplies, faster transportation and safe depots. This process took months or even years before a campaign was launched, and still had to be done during march. The next rule was organized marching, because an army on the move was always more vulnerable than it was in battle. The Romans made sure to minimize this vulnerability as much as possible. Experienced cavalrymen were always sent ahead as scouts, while the precious supplies and baggage was sandwiched between the best units, which all maintained proper intervals, making it easier to maneuver in the event of a sudden attack. The baggage too was organized under their own standards, just like the soldiers, with experienced non-combatants chosen to lead each group. This ensured that if under attack, the non-combatants would remain organized and not spread chaos among the troops. And if an enemy attack was almost certain, soldiers could be told to march with swords drawn. The third rule the Romans always followed was taming the land. Each of their armies was composed of a few soldiers experienced in construction and engineering, who could map out and lead massive projects through the hands of the entire army. There are a lot of fascinating examples of what a coordinated Roman field army was capable of. When fighting the Germanic Chadi tribe, who liked to hide in dense vegetation, Emperor Domitian ordered his Roman army to cut down entire forests just to get to them. When fighting local tribes in northern Hispania, the Romans built roads along the summits of hills and mountains, thus securing the advantage of the high ground. And Gnaeus Domitius Corbulo used his army to dig out a channel that connected the Rhine and Meuse rivers, giving the Romans a strategic head start. Taming the land also extended to constructing marching camps every evening, which was a fundamental Roman rule when in foreign territory. Soldiers should never go into battle after a long march, and these forts allowed them to rest and sleep without fear of attack, because even a superior force would think twice before attacking a Roman marching camp. They would have to cross the surrounding ditch covered in hidden caltrops and stakes, while taking a barrage of arrows and bolts from the towers above, and potentially be outflanked by sally-outs from the other gates. It would be far more preferable to just fight the Romans when they come out, which is why there are very few mentions of Romans being attacked at night. Also, if the coming battle turned out to be a disaster, Roman survivors could always fall back, regroup, and mount a defense from the nearest fort. Before we carry on, I would like to thank World Anvil for sponsoring this video. They are the ultimate solution for all your worldbuilding, storytelling, and gaming needs. 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With the enemy in sight, it's now time for the battle itself. And though not always the wisest option, it was a Roman rule of war to always take the field and offer battle. The Romans believed it was better to offer the challenge than to be challenged, and they also understood very well the psychological benefits that forming up for battle had on the minds of soldiers of both sides. In the event that the enemy refused to accept battle, a wise Roman general would be keen to exploit this as a certain sign of weakness and fear, which even if not true would greatly boost the confidence of his men, which would already put them in a far better position. It is important to understand that combat in the field was not so much decided by weapons as it was by morale, and the wisest generals knew this. In other words, you don't win a battle by just killing the entire enemy army. In fact, the majority of defeated armies never actually died in combat, but either scattered in the retreat, surrendered, or were killed in the ensuing route. In simpler terms, this means that in order to win a battle, you only have to ensure that the morale of your men always stays higher than that of your enemy. And yes, while simply killing a lot of the enemy or having braver individuals could achieve this, it could also be impacted by making sure your men were well rested and sated, and by inspiring confidence in them or terrifying the enemy. The famous Roman discipline and training always gave them an edge in morale, implying that if the battle was actually fairly even with no external factors at play, the enemy would still likely lose in the long game, when fatigue and exhaustion start to take a toll. Unless of course, some trickery was at play to even the odds of morale. So going back to Romans always taking the field, this yielded a good boost to morale early on. Before the Battle of Pharsalus, Caesar did this with utmost excellency, challenging Pompey's vastly superior force situated on higher ground, and Pompey's extra caution not to engage only worked against him, as his soldiers started to lose faith in him. Only on very rare occasions would a Roman leader choose to do the opposite and fake weakness in order to incite the enemy to attack. This was extremely risky and took a great toll on the morale of the men, so it was only done as a last resort. The rule of always taking the field also extends towards selecting the proper field for battle, and an experienced commander would always make sure it presented some kind of advantage for him. Higher ground was the best, as it was easier to see, fight, and charge from above, with the opposite being true for the enemy below. As a general rule, if the enemy had superior cavalry, then choosing rough, uneven, or forested ground should be preferred, and if the enemy had overwhelming numbers in general and threatened encirclement, having a flank against a natural obstacle like a river would be much better, as it would require only one flank to be guarded. A Roman general was expected to take in all these considerations and evaluate the best possible way to deploy his troops for battle. When facing the Teutons at Aquae Sextiae, Gaius Marius placed his troops on a hill to negate their inferior numbers, but knowing that a head-on battle might not win the day, he concealed a group of 3,000 soldiers in a forest nearby, who later charged at the enemy's flank and won the day. A good general would also pay special attention to minor elements like the direction of the sun, wind, and dust. Troops blinded by the sunlight or dust would fight at a disadvantage, and the direction of wind was enough to dull the charge of one side while accelerating that of the other, a fact exacerbated by the wide shields they would carry in front of them. The next Roman rule for war was using standardized units in battle. Now, in previous videos I couldn't stress enough about just how non-standardized the Roman army was on a small scale, with each soldier in any unit having a unique helmet, armor, and weaponry, but on a larger scale they were actually quite standardized. Every imperial army was made up of cohorts of either legionaries, highly trained Roman heavy infantry, or auxiliaries, support units made up of non-Roman infantry and cavalry fighting in Roman style and formations while retaining some local touches. Because of this very simple army composition, Roman generals had it easier than their Greek counterparts for example, whose armies were full of different types of units, each of a different size, martial culture, and way of fighting. Commanding such armies was always a daunting task for commanders who didn't know the strengths, weaknesses, and combat styles of alien units, while a typical barbarian army lacked much variation in their unit types altogether, and so couldn't employ complex maneuvers and support each other in battle. This was not the case for Roman generals, who could always resort to tradition when managing the units at their disposal. Any Roman officer who was let's say transferred to lead another army on the other side of the empire could easily transfer his skill and experience onto the new army, which would have the same unit types, formations, and army management to operate in exactly the same way, except maybe for some local trends or a few auxiliary units that had a unique skill set. But overall he could simply follow the book and repeat the strategies of his predecessors. On the plus side this allowed for more consistent victories, which the Romans were undoubtedly known for, but on the downside it allowed Rome's enemies to more or less know exactly what they were dealing with every time, and eventually learn how to fight the Romans more effectively. Regardless of the simple army composition, understanding the strengths and weaknesses of each unit was of paramount importance. For example, some auxiliary cohorts would consist of light infantry, who were very flexible and could be combined with the cavalry to bolster their numbers. Their speed allowed them to keep up with the cavalry or even share their mounts, only to dismount at a close distance with the enemy and catch them off guard. Vegetius confirmed that even the best cavalry struggled to deal with this tactic. Other auxiliaries were composed of heavy infantry. They were often used to either guard the flanks of army or be the first line of attack. Despite their second-class reputation, auxiliary heavy infantry were often capable of winning battles on their own, which is what happened at Mons Graupius, while the legions in the back acted as mere spectators. When the enemy routed, auxiliary cavalry was often unleashed to pursue, rack up the kills, and keep the enemy from regrouping, which made a victory truly decisive. Their speed and ground-shaking charges were great at damaging morale and quickly closing the distance with the enemy, leaving them little time to react. Last but not least, legionary heavy infantry was the most important element in any Roman army, and was often held in reserve. Ordering the legions forward was the ultimate sign that a Roman general was seeking to decide the battle here and now, and there was close to no one who could hold them off for long. But for the legions to operate properly, they must be protected from enemy cavalry, missiles, and flanking attacks by the aforementioned support units. If this was done, a Roman general could rest assured that the aggressiveness, discipline, and dogged determination of the legions would crush any enemy of the age. The final rule for Roman warfare was expertly carrying out field maneuvers. We all saw reconstructions of battles where one side very easily flanked the other with cavalry to win the day. In truth, even simple maneuvers like this across a battlefield spanning kilometers could take hours to be executed. Emperor Nero's long flanking march at the Metaurus river likely took hours to complete. Orders also took a long time to reach their destination, and the situation might very well change by the time they arrive, which would require counter-orders to be sent which could potentially cause confusion. As far as we know, each Roman century of 80 men would operate autonomously on the battlefield, and would each do what they thought was right for the moment, unless ordered otherwise. Expert field maneuvering extended even onto the proper positioning of the general during battle. Leading from the front like Caesar at the Battle of Munda was very heroic, but quite risky and went against Roman tradition. Not only would a general be risking himself getting killed, but he also couldn't see what was happening across the battle line. Instead, as stated by Onesander, a good general would ride by the ranks on horseback, show himself to those in danger, praise the brave, threaten the cowardly, encourage the lazy, fill up gaps, transpose a unit if necessary, bring aid to the weary, and anticipate the crisis, the hour, and the outcome. During the Battle of the Coligne Gate, Sulla had to gallop all the way to his wavering left flank in order to salvage the situation and keep them from routing. Now, many of you might be asking yourselves, how did Roman generals learn all this, from supplying tens of thousands of men to the art of leading them in battle? Well, the answer is quite surprising. Unlike today, Roman generals had no formal military education. There were no schools for commanders or doctrines for military knowledge. Instead, Roman generals were elected for being quick learners, good judges of character, having good public reputations, and of course, prior skill and experience. The best Roman generals learned from scattered records of historic battles and Roman values and principles, paying close attention to what their predecessors did before them, and they followed them so well that we were able to create six rules for war that almost every general across centuries would loosely follow, each with his unique deviations pertaining to his unique principles and experience. So by today's standards, Roman generals would be nothing more than self-taught amateurs, capable of either moments of great genius or inexplicable blunders. Nobody represents this better than Gaius Julius Caesar, one of the greatest generals in human history, though even he had a skill curve to his military tactics. In one of his first battles, fighting against the Helvetii, he hatched an overly complicated and naive plan involving a full night's march of part of his army for a surprise two-pronged attack, which only resulted in confusion that almost ended in disaster had the enemy capitalized off it. Caesar almost lost his army and his flawless military career before it even began. What do you think about this Roman system of generalship, and are there any Roman rules for war that we missed? Let us know in the comments below. A special thanks from me and the team goes to our Patreons for helping us create this video. Please consider joining them to help us increase our upload speed, and if you can't, just watch some more of our videos about similar topics. Thank you, and I hope to see you in the next one.