The most crucial conflicts in history have not always been fought on open fields, but rather in whispers behind palace walls, coded messages sent across borders, and shadows cast by invisible characters.
From ancient empires to digital superpowers, intelligence, the secret collecting and strategic use of information has been diplomacy’s silent partner, warfare’s hidden hand, and the quiet force that has determined nations’ fates.
Long before satellites orbited the earth and cyber-warriors penetrated digital defences, monarchs and emperors relied on spies, scouts, and informants to spot threats, manipulate competitors, and consolidate power. Intelligence work, by definition, operates on the edges of official history, with its agents unknown, wins unacknowledged, and failures buried. Nonetheless, its impact has been lasting, revolutionary, and frequently decisive.
Ancient foundations
Intelligence originated in Mesopotamia, Egypt, China, and India. In these early civilizations, monarchs relied on a network of informants, scouts, and ambassadors to gather information about adversaries, allies, and internal rivals. Ramesses II (1303 BC – 1213 BC) planned to undertake a military assault to regain the city of Kadesh which is known as modern-day Syria. He was misled by two captured Hittite spies who purported to be deserters. These men falsely reported that the Hittite army, led by King Muwatalli II (1295 to 1272 BC), was far to the north, providing Ramesses with false security. Ramesses marched his army forward, trusting their information and dividing it into several sections. However, he quickly apprehended more enemy scouts, who, when interrogated, disclosed the truth that the Hittite army was indeed hiding quite close to Kadesh, ready to ambush the Egyptians. While both sides claimed victory, the incident illustrates early use of:
- Human Intelligence (HUMINT): through captured spies and interrogations by the Egyptians
- Deception operations: by the Hittites to mislead and divide Egyptian forces to minimise the strength
- Strategic reconnaissance: as a critical failure on the Egyptian side until the deception was uncovered
The incident, which is documented in temple inscriptions and the so-called ‘Poem of Pentaur,’ is one of the most well-known examples of ancient intelligence, proving that even in the 13th century BCE, state actors recognized the potency of deception, counterintelligence, and psychological warfare. Pharaohs in ancient Egypt also employed an intricate bureaucracy that included officers in charge of reporting on local matters.
One of the first recorded treatises on intelligence may be found in the Indian work Arthashastra (approximately 4th century BCE), credited to Emperor Chandragupta Maurya’s advisor, Kautilya (also known as Chanakya). The text describes a complex espionage apparatus comprising double agents, hidden informants, and psychological operations. In Book 13 of the Arthashastra, Kautilya outlines how a king can demoralize enemy forces by employing psychological manipulation: “Soothsayers, readers of omens, astrologers, reciters of Puranas, intutionists, clandestine agents, those who helped the king perform the tricks and those who had witnessed them shall advertise them inside his own territory.”
Kautilya is stating that trusted public figures (priests, astrologers, and spies) should propagate carefully produced myths, omens, and ‘miraculous’ happenings to manipulate public sentiment and strengthen the ruler’s power. This is a textbook illustration of information operations and psychological influence in ancient statecraft. Kautilya’s ideas, which emphasised the need of deception and counterintelligence, is still considered a cornerstone of traditional strategic thought.
In ancient China, Sun Tzu’s The Art of War (circa 5th century BCE) also placed great importance on intelligence. Sun Tzu classified spies into five types and stressed that victory often depended on superior information.
According to Sun Tzu, ‘Local Spies’ are recruited from the opposing territory’s resident population. ‘Inside Spies’ or insiders in the enemy’s government, army, or administration. ‘Reverse Spies’ are enemy operatives who have been captured and recruited to work for your side. ‘Doomed Spies’ are dispatched with false intelligence, knowing they will be apprehended. ‘Surviving Spies’ who return with intelligence and live to be employed again.
Rome and the classical world
The Roman Empire institutionalized intelligence to a greater extent than many previous empires and civilisations. The Frumentarii, originally a logistics corps, grew into an intelligence service for the emperors of Rome. They acquired intelligence on enemy armies and tracked potential dangers to the emperor and the empire.
During his wars in Gaul, Julius Caesar, a military strategist, relied largely on scouts and informants to gather intelligence. Roman generals used code messages and different types of encryptions to protect communications, establishing early precedents for secure transfers.
Medieval and renaissance Europe
The Middle Ages saw the gradual spread of organised intelligence operations among European rulers. The Catholic Church, feudal lords, and kings all maintained informant networks. During the Crusades, both Christian and Muslim forces used spies to obtain intelligence.
Espionage became more sophisticated during the Renaissance. In 16th-century Europe, the advent of modern diplomacy fueled the expansion of intelligence activities. Italian city-states like Venice and Florence created early forms of secret agencies. Venice, for example, maintained a well-organised espionage network to preserve its economic interests and prevent political subversion.
In England, Queen Elizabeth I’s spymaster, Sir Francis Walsingham, built an effective intelligence network to uncover plans against the queen, notably the Babington Plot, which sought to kill Elizabeth and install Mary, Queen of Scots on the throne. Walsingham employed ciphered messages, surveillance, and a network of agents throughout Europe to dismantle the plot.
18th and 19th Centuries
As European empires spread over the world, intelligence collection became a critical element of colonial administration. The British Empire, in particular, established intelligence networks in India and the Middle East to track uprisings and geopolitical developments.
During the American Revolutionary War, both British and American troops used spies. George Washington formed the Culper Ring, a group of secret agents that gave useful intelligence about British army movements.
The Napoleonic Wars increasingly institutionalized intelligence. To crush dissent and acquire information, Napoleon Bonaparte used a centralized secret police force as well as a spy network. His opponent, the Duke of Wellington, likewise used reconnaissance and informants to develop his tactical strategy.
By the 19th century, the telegraph had revolutionized intelligence communication, enabling for speedier information transmission and the creation of signals intelligence (SIGINT).
The World Wars: Intelligence comes of age
World War I marked a turning point in the professionalisation of intelligence. For example, during World War I, British intelligence in Cairo was instrumental in fueling the Arab Revolt against the Ottoman Empire. T.E. Lawrence (Lawrence of Arabia), a British intelligence officer and archaeologist, collaborated with Sharif Hussein of Mecca and his sons, particularly Faisal, to plan guerrilla operations. Lawrence offered the British High Command with tactical advice, finances, and arms, as well as intelligence on Ottoman locations. The programme was overseen by the Arab Bureau, a British intelligence and propaganda cell headquartered in Cairo.
Cryptography and code-breaking were vital to the military effort. The British constructed Room 40, a clandestine team tasked with intercepting and decoding German communications. Its most notable accomplishment was the deciphering of the Zimmermann Telegram, which helped bring the United States into the war.
During World War II, intelligence capabilities expanded to unprecedented levels. The Allies and Axis nations created massive intelligence bureaus. The British Government Code and Cypher School at Bletchley Park, directed by people such as Alan Turing, successfully cracked the German Enigma code, revealing important information about Nazi operations.
In the United States, the Office of Strategic Services (OSS) was founded in 1942 as the forerunner to the Central Intelligence Agency. The OSS oversaw espionage, sabotage, and psychological operations behind enemy lines.
The Soviet Union’s intelligence services, especially the People’s Commissariat for Internal Affairs (known as NKVD) and later the ‘Komitet gosudarstvennoy bezopasnosti’(KGB), carried out significant espionage against both Axis and Allied powers. Soviet agents infiltrated important organisations in the US and UK, laying the framework for Cold War espionage.
The Cold War era
The Cold War established intelligence as a permanent component of statecraft. The competition between the United States and the Soviet Union resulted in an arms race for nuclear weapons and intelligence capabilities. Spy agencies such as the Central Intelligence Agency (CIA) and KGB competed for influence around the world. Espionage reached practically every corner of the globe, from Berlin to Angola to Afghanistan. Notable episodes of intelligence during the Cold War include the U-2 incident, the Cuban Missile Crisis, and the defection of high-ranking operatives such as Kim Philby. Electronic intelligence (ELINT), satellite reconnaissance, and aerial surveillance have all grown in popularity as technology has advanced. However, Human intelligence (HUMINT) remained critical, with agents acting undercover in dangerous environments during the Cold War.
Post-Cold War
The conclusion of the Cold War resulted in a short reduction in the prominence of intelligence services, but 11 September 2001 attacks heralded a new era. Intelligence has become vital to the global war on terror. Agencies increased counter-terrorism operations, monitoring, and data collection particularly on terror organisations. New laws and technologies enabled governments to more closely monitor suspects, but they also prompted ethical questions about privacy and civil liberties. The establishment of the United States Department of Homeland Security and the restructure of the intelligence community mirrored the evolving nature of threats, ranging from rival superpowers to decentralised terrorist networks.
The digital age
In the twenty-first century, intelligence has increasingly moved to the digital sphere. Cyber espionage, disinformation tactics, and mass surveillance have all become important aspects of global power competition. Nations such as China, Russia, the United States, and others conduct hacking operations against government and corporate targets. The theft of intellectual property, manipulation of social media, and attacks on essential infrastructure highlight new frontiers in intelligence warfare. Whistleblowers like Edward Snowden exposed the huge breadth of digital surveillance carried out by agencies like the National Security Agency (NSA), igniting global debates over the balance of security and privacy. Artificial intelligence, machine learning, and big data analytics are already playing a growing component in intelligence analysis, generating new challenges about supervision, accountability, and the human role in decision making.
Continuity and change
Intelligence’s history is marked by both continuity and transformation. While means, targets, and technology have evolved tremendously, intelligence’s vital objectives of providing strategic insight, anticipating risks, and influencing outcomes remain consistent. From ancient royal spies to modern surveillance algorithms, intelligence has shaped and been shaped by the tides of time. As we progress deeper into the digital era, the necessity to understand the history of intelligence becomes more pressing than ever. In a world where information can be both a weapon and a shield, the shadows of history continue to haunt the present and future.
(The author is a Senior Researcher, Bandaranaike Centre for International Studies, and holds a MSc in Strategic Studies from Nanyang Technological University in Singapore)
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The views and opinions expressed in this article are those of the author, and do not necessarily reflect those of this publication