Sir Algernon Sidney (1622-1683), born at Penshurst in Kent, was the grandson of Sir Phillip Sydney, 2nd Earl of Leicester. He fought as a Parliamentarian during the Civil War and was wounded at Marston Moor. During the interregnum he came to resent Cromwell's usurpation of power but fled to the continent at the Restoration. Although he returned to England in 1677 he was always considered dangerous and unreliable and in 1683 was implicated in the Ryehouse Plot to assassinate King Charles II. He was tried with the Duke of Monmouth and Lord Russell, found guilty on slender evidence and executed.