Algernon Sidney
Portrait of Sidney Algernon on the frontispice of the French translation Discours sur le gouvernement (Discourses Concerning Government), The Hague, 1702. Algernon Sidney or Sydney (14 or 15 January 1623 – 7 December 1683) was an English politician and member of the Long Parliament. A republican political theorist, colonel, and commissioner of the trial of King Charles I of England, he opposed the king's execution. Sidney was later charged with plotting against the King, in part based on his work, Discourses Concerning Government, used by the prosecution as a witness at his trial. He was executed for treason. After his death, Sidney was revered as a "Whig patriot–hero and martyr".