Efforts to use espionage for military advantage are well documented throughout history. Sun Tzu, 4th century BC, a theorist in … See more

Modern tactics of espionage and dedicated government intelligence agencies were developed over the course of the late 19th … See more

• Reign of Elizabeth I of England
• English Commonwealth
• American Revolution See more

Many modern espionage methods were established by Francis Walsingham in Elizabethan England. His staff included the See more

The 18th century saw a dramatic expansion of espionage activities. It was a time of war: in nine years out of 10, two or more major powers were at war. Armies grew much larger, … See more

Civil intelligence agencies
In Britain, the Secret Service Bureau was split into a foreign and counter-intelligence domestic service in 1910. The latter, headed by Sir See more

Spying has sometimes been considered a gentlemanly pursuit, with recruiting focused on military officers, or at least on persons of the class from whom officers are recruited. … See more