. . . During the Late Roman Republic


The Role of Military Intelligence

The role of intelligence in military operations is typically to:

  • Spread disinformation
  • Gather information about the enemy–his supply sources, his allies, the number and composition of his forces, etc.
  • Use assassination . . . if it'll achieve or help to achieve some pivotal, tactical or strategic purpose.
  • Use sabotage to disrupt the enemy's operations and effective management of operations
  • Supply allies and rebel forces with training, money and equipment
  • Intercept enemy communications

The Romans were no different from us: they pursued most of these very same objectives.

Unlike us, however, they didn't have a formal centralized organization like the CIA, MI-6, or ANBw that centrally supported and directed such operations. Instead, they used scouts and spies attached to the legionary forces as their active agents, and they used other resources to gather information to achieve their intelligence objectives.


The main "intelligence gatherers" for the Romans were:

  • Equites running point for a legionary force– Scouts on horseback who preceded a legionary force (during the Roman Empire these evolve to become the Procursatores) on the march.
  • Exploratores— Scouts, usually riding on horseback, who ran farther afield from the legionary forces, like the British Exploratory Officer of Napoleonic times.
  • Speculatores–The covert agents, the "secret agents", of the Late Roman Republic (during the Roman Empire these evolve into a secret police force serving the Emperor as well. During the Principate and the Empire, speculatores also refer to specific groups and ranks in the Roman army that have nothing to do with spying .)

    Speculatores might be soldiers, citizens, slaves, etc. In short, anyone who might be able to infiltrate enemy towns and positions, while doing so undetected. They might infiltrate enemy positions by posing as deserters, refugees, merchants, and so on. Gnaius Pompey the Younger, for instance, during the Spanish War, had four of his speculatores–three slaves and one legionary– unmasked and subsequently executed by Caesar's forces. In 46 BC, Metellus Scipio sent two Gaetulians with a group of deserters into Caesar's camp at Ruspina to try and gather some intelligence about Caesar's defenses against elephant charges; those two instead defected to Caesar and gave him extensive information about Scipio's forces.


Other means for gathering intelligence that the Romans used were:

  • Legionary commanders "seeing for themselves"
  • Allied tribes or countries
  • Provincial governors and their staffs
  • Diplomatic missions
  • Social gatherings (e.g., marketplaces, public baths, taverns, political get-togethers, dinners etc.)
  • Whores and other local riff-raff
  • Merchants
  • Locals (who might just be aiding both sides just to get them out of the neighborhood more quickly)
  • Refugees and deserters
  • Prisoners: captures slaves, citizens, and/or soldiers. After interrogation, they might be fed false information and then be sent back to the enemy; or they might be recruited as "moles"; or they might be recruited or coerced into acting as guides
  • Runners or dispatch riders
  • Watch & signal towers, where they existed


What sorts of information were they most interested in? Subjects of interest fell into three main categories:

  1. Geography and Terrain, such as:
    • Approaches
    • Escape routes
    • Topography
    • Harbors
    • Water sources
    • Food sources
    • Weather
    • Tides
  2. Social and Political Factors, such as:
    • Population
    • Social/Political Institutions
    • Quality of Leadership
    • Trade/Financial situation
    • Nature of the area's inhabitants
    • Prevailing attitudes of the area's inhabitants
    • Allies and Enemies
    • Food supply
    • Religious beliefs/rituals/holidays
    • Any other factors that might be exploited
  3. Military Factors; such as:
    • Quality of Leadership
    • Communication lines
    • Sources of Supply–material and food
    • Military unit sizes, types, dispositions
    • Outpost locations
    • Weaponry favored the enemy
    • Tactics favored by the enemy
    • Habits, routines
    • Fortifications–location, type, number and numbers of troops

Knowledge such as this could be very critical to ensuring the success of an upcoming battle or campaign.