A list compiled by spymaster Robert Cecil gives an insight into the beginnings of the secret service, says historian

For more than a century, it lay undisturbed in the National Archives: a single sheet of paper, headed The names of the Intelligencers, with the power to unveil a hidden network of secret Elizabethan spies.

Now, the 428-year-old secret dossier of Robert Cecil, spymaster to Elizabeth I and the man who discovered the 1605 Gunpowder Plot, has been pieced together using this key document. It reveals how Cecil set up and used a clandestine espionage network to spy on European monarchs for the English throne.