William Herle (died 1589[1]) was an Englishman who was both a Member of Parliament and the county sheriff; he was also a privateer and spy while imprisoned in the Marshalsea prison in 1571.
He smuggled letters from William Cecil and Lord Burghley about people involved in the so-called Ridolfi plot, which was a Roman Catholic plan to assassinate the Queen and replace her with Mary, Queen of Scots.
This brought Herle to the attention of William Cecil, who hired him in the mid-1560s to travel and supply the allies in England.
Eventually, Margaret, Duchess of Parma, a Spanish regent in the Netherlands, asked Elizabeth I to stop Herle.
Herle would have gotten the death penalty for being a pirate, but often managed to escape through a loophole where he stayed in jail and wrote about his experiences.