John Cooper's The Queen's Agent is an exploration of the rise of espionage in Elizabethan England, and is just as thrilling as any modern spy novel. At the center of this forgotten corner of history is spymaster Sir Francis Walsingham.

How close did Elizabeth I come to being assassinated? To anyone familiar with the icon-like portraits of the Virgin Queen, the question may sound bizarre. Henry VIII’s younger daughter tends to get a good press these days, an intelligent and politically dexterous woman who fought for her independence in a patriarchal world. We remember her reign as a period of comparative calm after years of religious strife, when the English people prospered and cultural life underwent a remarkable renaissance. But there was another dimension to life in Elizabethan England: one shot through with violence and fear, nastier than the official portrait of a nation at peace, but – for a historian like me – a whole lot more fascinating. In this reign of Elizabeth, the stability of Protestant England was just an assassin’s bullet away from ruin. Protecting the Queen from harm, monitoring the activities of Catholic cells within England and disrupting their activities in continental Europe, was principal secretary Sir Francis Walsingham: a man who gave his every waking hour to keep the Elizabethan regime secure.

Researching The Queen’s Agent, I came to two unexpected conclusions about the rise of espionage in Elizabethan England. I knew this was a time of innovation in techniques like cryptography and forgery, and so it proved to be: Walsingham employed men who could crack apparently unbreakable codes, and use chemicals to make writing invisible. What I hadn’t fully appreciated was the nature of the relationship between spy and spymaster. Walsingham’s operatives were his own clients, personally loyal to him and paid out of his own pocket. In this sense, the Elizabethan security services look different from their modern British equivalents MI5 and MI6 or the CIA. The Tudor court was a political and religious maelstrom, with factions constantly maneuvering to influence policy. In this environment, reliable intelligence could give you the edge. A foreign-policy hawk and a Protestant of deep conviction, Walsingham could see that England’s future depended on arming herself against Catholic Spain. His network of agents at home and abroad gathered the proof to persuade Elizabeth to defend herself and her nation, albeit only at the eleventh hour.

The second thing that struck me about Walsingham was his extraordinary ability to persuade his enemies to work for him. Walsingham’s greatest triumph was his discovery of the Babington plot to break Mary Queen of Scots out of her captivity in northern England and enthrone her in Elizabeth’s place, assisted by troops from France or Spain. Walsingham was intercepting Mary’s ciphered letters from the start, which helps to explain why this plot is so well documented in the national archives. But how did he gull Mary into believing that she could talk to her supporters without being overheard? The answer opens up a world in which loyalty could be bought for money – even the loyalty of an ordained Catholic cleric. The Babington plot would never have hatched had it not been for Gilbert Gifford, a shadowy young man who studied in Rome to join the Catholic mission to England, but was then turned by Walsingham into one of his deadliest agents. Gifford was able to convince Mary to smuggle messages to Anthony Babington concealed in barrels of beer; messages which were read by Walsingham’s men before being allowed to reach their destination. The plot yielded the evidence on which Mary was beheaded in 1587. Gifford was one of several priests recruited by Walsingham as double-agents to report from the Catholic underground, a devastatingly effective exercise in infiltration which our modern security services would recognize.

Was Elizabeth ever truly in danger, or were these plots actually in the control of the government, a brutally cynical means of justifying the repression of Catholics? The crown certainly played them for all they were worth, printing official histories and prayers of thanksgiving for the safety of the Queen. But propaganda is at its most effective when it contains a kernel of truth. Having studied all the conspiracies unearthed by Walsingham and his agents, I can see that some of them were more manufactured than real. John Somerville, who set out on a solo mission to kill the Queen and ended up strangling himself in prison, was clearly suffering from delusions. William Parry was a double agent, pretending to talk treason with his Catholic friends while secretly reporting on them to the government; when news of the ‘Parry plot’ broke, he was in too deep to save himself. But other conspiracies were genuine, a clear and present danger to the state; the only explanation which makes sense of Walsingham’s constant sense of fear. The likeable young Francis Throckmorton, for instance, was one link in a chain that led from the French ambassador’s house out to Mary Queen of Scots, the Guise family in France and onward to Spain and Rome. When Throckmorton was picked up in London, a Catholic invasion fleet had already begun to assemble in Normandy. It does not stretch the truth to imagine a French armada in 1583, five years before the famous Spanish assault on the England of Elizabeth.

The danger in writing a book like this is to fall back on the conventional stereotypes: wicked Catholic plotters or brave Catholic martyrs, depending on your personal point of view. This is something I have tried to avoid. Historians sometimes forget that the subjects they write about were real people, deserving of dignified treatment. Brave young men went to horrible deaths for seeking to return Elizabethan England to the Catholic fold, and their stories demand to be told. Most Catholics were loyal to the Queen insofar as their faith allowed. Some, however, were not. The fact that certain Catholics did plot to assassinate Queen Elizabeth should not tar the entire community with disloyalty, but it does show Walsingham in a different light. His armory of torture and intimidation may look vile to the modern world, but for him the ends justified the means. As Walsingham told Mary Queen of Scots to her face, his conscience was clear.