From James Bond, Jason Bourne, and every other spy with the initials J.B., to real life spies, government agencies, and our own vivid imaginations, we seem to really like spies. There’s even museums for espionage. Between the gadgets, the tactics, the webs of lies and secrets, it is admittedly compelling stuff. Espionage is as old as recorded history. So let’s talk espionage in the ancient world. Quietly, so nobody overhears….
Should I even bother with my usual opening about how little we know? I guess in this case it’s defendable; spies aren’t supposed to leave a paper trail, so not having a lot of evidence just means they were really good at their jobs, right? It is clear espionage in the Greco-Roman world was widespread, but most of our knowledge comes from accounts discussing how to defend against spying, rather than works about spies directly. Aeneas Tactius, a 4th century BC military writer provides the bulk of our literature. His only surviving work, “How to Survive Under Siege”, talks about, well, it’s obvious.
Tactius’ work lays some of the ground rules for Greek espionage and insight into typical clandestine operations. κατάσκοποι (kataskopoi), spies or scouts, offered military leaders both important intelligence, and possible means of sabotage. Tactius’ work covers smuggling, army signals, infiltration, passcodes, and the like.
Of course in the Greek world, one of the most common intelligence sources was the mercenary. Mercenaries were common, recruited from all over, and offered a first-hand assessment and knowledge of local matters. Persian kings would also have Greeks in their courts, and Xenophon’s Anabasis is the story of his experiences as a mercenary for the Persians.
For the Greeks, espionage wasn’t necessarily a simple matter. Issues like guest-friendship, mercenary troops, multi-state alliances, and multi-state armies made it a little more difficult to pick out friend from foe. Xenia (guest-friendship) left both a figurative and literal open door for spies. Greeks made plenty of diplomatic and familial alliances as well. Defense against spies was difficult, to say the least. Short of extreme measures such as ξενηλασία (xenelasia), “driving out strangers”, literally expelling all foreigners from the city—a plan nobody but the Spartans and Donald Trump have ever thought was even remotely a good idea—the fact that there were probably a few spies running around appears to be just something they lived with. Some stories from surviving literature show military leaders purposefully leaking false information, counting on the fact that their cities and armies were full of spies. Tactius at the least gives reasonable advice on how to overcome some of these issues in the event of a siege, such as making sure verbal passwords can’t be equally expressed by another word in another dialect (remember, there were lots of dialects in ancient Greece), or only allowing loyal guards with ties to the city (read; families) as gatekeepers.
On the Roman side of things, our evidence isn’t much better. We have some sources that discuss information gathering, and works like Caesar’s memoires offer first-hand examples. For the most part, espionage was just not a “Roman thing”; rather than a system of scouts, spies, and informants feeding generals information, the Romans preferred just sending an army to fight whoever they found, wherever they were. Can’t really blame them, for the most part it worked.
That said, the Romans didn’t operate completely in the dark. They were ballsy and ran a nearly unstoppable military juggernaut, but they weren’t invulnerable. Intelligence operations were still useful. Within the standard Republic legions were contingents of cavalry, useful for scouting, and specialists called “speculatores”. For Caesar, these seemed to be the go-to people for carrying out basic spying. Caesar also talks a decent amount about Gauls he employs for more reliable information. When he decided to invade Britain, Caesar was basically flying blind; his first trip across the pond was essentially just a recon mission to find out what the hell was on the other side. Coincidentally, the Britons must have had a much better intelligence network than Caesar, because they had an army ready and waiting for Caesar at the landing site!
By the Roman Empire, speculatores, and to a lesser extent exploratores (guess what they did), gave way to other groups. Frumentarii, who were originally logistics officers (word literally means “grain dudes”), made decent intelligence officers for the Empire, since their duties naturally involved travelling to various places and interacting with lots of people. Spying wasn’t just done on foreign nations, of course, and the frumentarii had a third function as a sort of secret police force. So Emperors basically used them like Gestapo agents. Or rather, Gestapo agents acted like frumentarii—the posers. Similarly, reference is made to curiosi, which seems a more general term for “spies”. By the Late Empire, the frumentarii were causing too many complaints among the populace, so Diocletian disbanded them. In their place were agentes in rebus, literally “general agents”. Notarii, whence we get notary publics, were basically bureaucratic secretaries in the Late Empire, and also served intelligence roles. Speculatores wound up serving as imperial bodyguards, mostly doing what we would today call “wet work”. The notable change in all these groups is that by the Late Empire intelligence shifted from the military (speculatores and frumentarii) to civilian control (agentes in rebus and notarii).
Espionage in the ancient world operated much like today. They used disguises, forged papers, recruited “assets”, created ciphers, and came up with other clever ways to carry out spy missions. Not everyone could be a spy, and the use of documents precluded the illiterate from some uses. Slaves also made good recruits for spies, since their status gave them a sort of natural cloak against attention. Obscurity was always an asset, and just like the Spanish Inquisition, nobody really expected the slave. There are some accounts of making special compartments in the soles of sandals to hide messages, which is about as technologically advanced as their gadgets got—the Aston-Martin DB5 wasn’t around yet. What the ancients lacked in fancy spy gadgetry they made up in cleverness though. Herodotus tells the story of Histiaeus, who wanted to return from Susa and the Persian court as tyrant of Miletus. To this end he needed to instigate a revolt, and found only one way to get the message out.
For Histiaeus, when he was anxious to give Aristagoras orders to revolt, could find but one safe way, as the roads were guarded, of making his wishes known; which was by taking the trustiest of his slaves, shaving all the hair from off his head, and then pricking letters upon the skin, and waiting till the hair grew again. Thus accordingly he did; and as soon as ever the hair was grown, he despatched the man to Miletus, giving him no other message than this- “When thou art come to Miletus, bid Aristagoras shave thy head, and look thereon.” Now the marks on the head, as I have already mentioned, were a command to revolt. Herodotus, Histories, Book 5.
Intelligence in the Greco-Roman world wasn’t so dissimilar from modernity then. While there wasn’t as much official activity (as far as we know), both the Greeks and Romans made use of spies. There wasn’t as large a need to break the ancient equivalent of the Enigma machine. Neither the Greeks nor Romans considered espionage an “honored profession”, which helps explain why there is not a lot of material to work with, and why they didn’t create their own versions of the NSA. For the most part, intelligence and espionage were informal systems of information gathering, making use of various existing groups in the military and civilian professions. The collection of alphabet agencies we have today probably would have been overkill for the Greeks and a “wussy” way to fight for the Romans.