Units of History - The Exploratores: Scouts of the Roman Army DOCUMENTARY

The Roman army is best known for its dominance on the battlefield. However, the physical strength of the force was just a portion of its recipe for success. Another key ingredient was its information dominance when it came to tactical and strategic warfare. This was made possible by the eyes and ears of the legions. Today, let's explore the unsung story of the scouts of the Roman army, the Procursatores, and the Exploratories. As an example, I've finally been able to delve into Stephen Leavitt's Freakonomics, Yuval Harari's Sapiens, and Stephen Hawking's A Brief History of Time. It's honestly been extremely liberating and a huge breath of fresh air for my ever-curious mind. You can check it out right now by clicking the link in the description below to get a 7-day free trial. In addition, the first 100 people will get 25% off a full membership. So check it out. Ancient armies needed cartographers and intelligence just as badly as modern forces, but didn't have anywhere near the amount of technology. The closest equivalent to a satellite view would be a rider on a hilltop. As a result, forces might be within miles of one another, and yet remain unaware of that fact until they literally bumped into one another. Thus, it became important for all armies to carry out reconnaissance of some form. This was especially true of armies with extensive logistical systems. Failure to scout properly could mean that your march took longer, suffered unnecessary attrition, or worse yet, got ambushed. Early Roman armies of the monarchy and nascent republic were rather unsophisticated in these but they didn't necessarily need to be. Their operations were usually close to home in familiar territory. A few riders out in front were generally enough to get the job done. However, as the legions expanded their scope of activities to the hill country of Samnium, or the island of Sicily and beyond, the demands of scouting greatly increased. What developed was a more robust approach to reconnaissance, in the form of the Procursatores. These were generally groups of mounted troops who fanned out in the close vicinity of the main army. They tended to stay well within a day's march of the infantry column and were expected to operate self-sufficiently. The Procursatores were not some specialized elite scouting unit. Rather, they were merely a group of troops who had been selected from the main army to fill the role as the situation demanded. As a result, their composition varied greatly. Rome's Equitae cavalrymen filled the role initially, but quickly passed on the torch to more capable allied and auxiliary troops. Caesar, for instance, famously employed Iberian, Gallic, and Germanic horsemen for many of these activities. In terms of their numbers, they were usually quite small in proportion to the overall force. For example, in Julianus' campaign against the Persians, his army of about 60,000 to 80,000 men employed a mere 1,500 Procursatores, or roughly 2% of the total force. Whilst deployed, the Procursatores primarily acted as a close screen for the army, who would make contact with any nearby forces. These patrols were maintained day and night, with their frequency being increased in dangerous territory. As such, they could intercept deserters, informants, enemy scouts, and troops. Another important role was that of pathfinder. The Procursatores were expected to explore the terrain immediately ahead and make recommendations on the army's best path forwards. This could be as simple as selecting which fork in the road to take to reach the objective. However, they also had to consider things like the availability of water, foraging opportunities, the danger of the terrain, and the presence of defensive high ground. Ultimately, generals had the final say on the course of the army, but ignored the advice of their scouts at great risk. The Emperor Valentinian, for instance, very nearly lost his life when he decided that the Procursatores had chosen a more difficult path than was necessary, and almost immediately fell into an enemy ambush. When a path was selected, the Procursatores also worked to secure that route. This involved cutting down trees, removing obstacles, and clearing traps. This advanced force might also be supplemented by light infantry and archers to disperse any token resistance offered by the locals or to flush out potential ambushes. A cleared path was not just important for the safety of the army, but also its mobility, which was one of the most important strategic tools in Rome's military arsenal. A final role of the Procursatores was to take part in the foraging duties of the army. This would be done in conjunction with troops assigned to the role of Aquatores, Pabulatores, and Lignatores. Such daily activities were just as vital as anything related to combat, since an army could only remain in operation so long as it was fed. We cover the topic of Roman army logistics in another video, which you can check out to learn more. While the Procursatores were certainly vital to the Roman intelligence operation, they did not fulfill all of its needs. For example, we mentioned that they were usually restricted to acting as a close screen of the army. The vast unknown beyond would be covered by the next category of scouts, known as the Exploratores. Caesar claims that they worked at a range of about 35 km, while Ammianus Marcellinus set a minimum of 30 km. As with the Procursatores, the Exploratores tended to be lightly equipped cavalry troopers, selected for an ad hoc assignment, rather than on a permanent basis. Oftentimes, the soldiers would be chosen from among the auxiliaries who made up the bulk of Rome's cavalry forces. However, this was not always the case. In Trajan's Dacian Wars, legionaries themselves were picked for the job. By the later empire, however, it does seem that the Exploratores were eventually organized into their own formalized units. Whatever the case, the men in question would have been screened for possessing the necessary skills and experience given the importance of the task at hand. Their primary role was that of a scout force, riding out from the main army in all directions to gain an understanding of the world around them. Such journeys could go on for days or weeks at a time, and the Exploratores were thus equipped to survive out in the environment on their own. One can imagine a detachment of them establishing some small base of operations by a recognizable landmark, from which to disperse and regroup periodically. As they traveled, they took notes on all kinds of things like geography, topography, troop positions, and recent events. This may have been observed first-hand or relayed to them by Rome's network of spies and informants in the field. For instance, a scout might discover that traveling along the eastern road for a distance of three days' march would bring the army to a small village, which had recently been occupied by a garrison of the enemy numbering no more than 100 men. A good eye and experience would be invaluable in this role. For example, smoke and fires indicated an encamped force, while a low, wide dust cloud suggested the movement of a large body of infantry, and a tall, narrow cloud meant the movement of cavalry. If line of sight on actual troops could be achieved, the little details mattered. What unit times were there? How many could be counted? Were they disorganized? Did they have their shields uncovered and their equipment ready for battle? In an age before detailed maps, these sorts of meant to provide the general with an up-to-date understanding of his surroundings, from which to piece together a plan of action. For instance, when two armies drew nearer, they would typically slow down, encamp, and begin to probe one another. Once again, the exploratories would be key in these activities. They might be sent on specific patrols to look for weaknesses in the enemy's Sometimes, the exploratories might get a little too close and even skirmish with elements of the enemy army, which would also have had its own scouts, pickets, and foragers milling about. When a specific action was to be undertaken, the exploratories would often be brought in for consultation. For instance, if a commander wished to make a daring multi-pronged night march against the enemy, it would be the exploratories who advised on potential approaches that could be taken. If a commander wished to give battle, the exploratories would give a detailed account of the battlefield to the general and his officers. Though it's never mentioned explicitly in our sources, one can imagine the use of simple military sand tables to convey the information fully. These descriptions would note any and all details which might be a risk or advantage to the army. For instance, the river can only be crossed at a few locations. These embankments make this hill unassailable from all but one side. This marsh is sufficient to prevent outflanking. These woods may hide troops. And so on. A failure by these men was almost always catastrophic. If they reported incorrect information, the army itself could easily be wiped out. In a more routine capacity, the scouting of the exploratories would often be used to determine the location of the army's daily encampment. This was a key part of Roman military operations, as a means to provide security for the troops and their supplies. An ideal camp would be placed on elevated, level ground with a good view of the surroundings and easy access to building materials and water. Pliny the Elder states that once a site had been selected, the exploratories would be required to get fires going, perhaps as a signal to the army or to provide a source of heat for warmth and food preparation. Once this had been done, the exploratories might have worked with the army engineers to mark and survey the site before the army vanguard arrived to start the actual construction work. Another important role of the exploratories was to take offensive action deep behind enemy lines. This meant that in addition to tracking units, they might also rustle their herds of cattle, disrupt their supply lines, or poison their water sources. Such tricks could slow or even cripple an enemy army, making it easy prey for the legions which were soon to arrive. Yet more aggressive actions were possible as well. Exploratories might set traps, plot small-scale ambushes, and even engage in targeted assassinations if the opportunity arose. One fantastic attestation to this is the gravestone of a man by the name of Tiberius Claudius Maximus. It recounts his distinguished career, which included two awards for bravery as a member of the exploratories in the Dacian War. Apparently, it was his unit that was tasked with hunting down the Dacian commander Decibulus. They managed to corner their target, leading Decibulus to slit his own throat. According to the tombstone and depictions on Trajan's column, Maximus reached the dying commander, severed his head, and brought it back to the emperor as a prize. For this, he was greatly rewarded. Such ruthless and effective men must have been exactly what Roman generals looked for in their scouts. While not explicitly stated by our sources, similar units of exploratories may have also been on the trail of Rome's other infamous enemies, such as Hannibal, Mithridates, and Zenobia. Occasionally, especially when combat was not necessarily expected, the legions would employ locals as exploratories. Such individuals could generally be counted on to already have a good understanding of the land and must have been used quite regularly. However, the few times we hear about them in our sources is when things went horribly wrong. One such incident occurred during the Roman invasion of Arabia. Here, a local seems to have led the infantry heavy army on a circuitous route through the desert, tripling the length of their march. The attrition, on top of other factors, eventually led to the ignominious retreat of the entire Roman force. Locals who provided accurate intelligence to Roman commanders were generally richly rewarded. But if things went wrong, they were always the scapegoats, even if it was an innocent mistake. Guides who failed in this way were summarily executed. Thus we have seen how Rome used a layered approach to information warfare, consisting of the procursatores, who acted as a close-range ring of patrols and skirmishers, in addition to the exploratories, who acted as a long-range ring of scouts and disruptors. Both were a key part of any military operation and were fundamental to the dominance of the legions across the centuries. However, they were just part of Rome's larger information-gathering operation. Stay tuned for future episodes, where we will get to cover the speculatores and spies of the Roman army. Be sure to like and subscribe for more content. And, as always, let us know what units of history you would like to see covered next.