Declaration of Lex Talionis
Early in the First English Civil War the Long Parliament threatened to retaliate in kind if the Royalists tried and executed John Lilburne and two other Parliamentary offices for treason. Lilburne later described this as the declaration of Lex Talionis, and it brought about a practical—rather than moral—mutual restraint by the parties to the war on how they treated prisoners of war. History Early in the English Civil War, John Lilburne, a prominent supporter of the Parliamentary cause who because of his radical views was known as "Free Born John", was captured by the Royalists during the Battle of Brentford while serving as a captain in the Parliamentary army. Moves were taken to try him and two other prisoners of war (Clifton Catesby and Robert Vivers), in the civil court of the Kings Bench as traitors. Elizabeth, Lilburne's wife, appealed to Parliament and on 17 December 1642 Parliament stated that it would hold the Judge and officials of the court responsible for the treatment of the three men, and if they were tried and punished would retaliate in kind against Royalist prisoners of war. This lifted the threat to the men and in May 1643 Lilburne was exchanged for Royalist