John Thurloe, the son of a rector, was born in Essex in 1616. He trained for the law at Lincoln's Inn and later became secretary of Oliver St. John, a leading figure in the House of Commons.
Thurloe was a strong supporter of Oliver Cromwell and in 1652 was appointed clerk to the Council of State. He became an increasingly powerful figure in the Commonwealth and in effect became the country's sole Secretary of State.
In 1653 Thuroe was placed in charge of intelligence department. In this post he employed spies to discover plots against Cromwell's government. He also hired mathematician John Wallis to establish a cryptology department that could break secret codes. With this information he was able to dismantle the royalist secret society, the Sealed Knot. However, Thuroe's attempt to kidnap Charles II ended in failure.
When Oliver Cromwell died Thuroe attempted to get Richard Cromwell to replace him as Lord Protector of the Commonwealth. The English army was unhappy with this decision and in May 1659, the generals forced him to retire from government.
On the Restoration Thurloe was dismissed from office. However, his life was spared in exchange for providing Charles II with important government documents.
John Thurloe died on 21st February, 1668.