Antiquity: Biblical, Greek, and Roman Spies
Before the internet, before written language, before countries as we know them, there were still spies, and there was still data theft. Espionage is sometimes cheekily known as one of the world's oldest professions, and just about every empire you can name employed networks of spies tasked with gathering intelligence on enemies both perceived and real. According to the A to Z of Middle Eastern Intelligence, "Egyptian hieroglyphs and papyri reveal the presence of court spies. From 1,000 BCE onward, Egyptian espionage operations focused on foreign intelligence about the political and military strength of rivals Greece and Rome." But one of the best sources of information about early intelligence-gathering is actually the Bible itself.
Spying and intelligence gathering is a major recurring theme in just about every political or military anecdote in the Bible. Moses and Joshua were both huge proponents of espionage, the former having a network of 12 spies, one from each tribe, who were tasked with sneaking into surrounding areas and gathering information on military and agricultural assets. The story of Samson and Delilah is, at its core, a story of intelligence gathering. Terry Crowdy, author of The Enemy Within: A History of Spies, Spymasters and Espionage, refers to Delilah, pictured in this Guernica painting, as "the first female secret agent in recorded history." Her mission, for which she was paid by Philistine lords, was to find through any means necessary the information needed to defeat a powerful enemy.
Interestingly, much of the espionage of this time period was actually counter-espionage--spies seem to have been caught at least as often as they were successful, and feeding false data to spies accounted for many major military victories. The battle of Kadesh, the earliest battle for which key details of tactics are known, was rich with espionage and counter-espionage. Hittite spies were sent, posing as deserters, to the pharaoh Rameses, aiming to convince him that Hittite forces were much further away than they actually were. But Rameses captured two not-so-effective Hittite spies and convinced them ("under repeated blows," says Crowdy) to tell the truth, at which point Rameses called up his reserves and was able to face the battle better prepared. And that counter-espionage only got more complex and nuanced.
The Greeks and Romans also used this sort of espionage, sending spies into enemy camps to learn military strategies and report back. Most of the examples that survived history are about the, well, inefficacy of these spies--seems like they were always getting caught, and often sent back with incorrect or incomplete information to lead their armies into traps.