Robert Catesby (3 March 1572 – 8 November 1605) was the leader of a group of English Catholics who planned the failed Gunpowder Plot of 1605. Born in Warwickshire, Catesby was educated at Oxford University. His family were prominent recusant Catholics, and presumably to avoid swearing the Oath of Supremacy he left college before taking his degree. He married a Protestant in 1593 and fathered two children, one of whom survived birth and was baptised in a Protestant church. In 1601 he took part in the Essex Rebellion but was captured and fined, after which he sold his estate at Chastleton.
The Protestant James I, who became King of England in 1603, was less tolerant of Catholics than many persecuted Recusants had hoped. Catesby therefore planned a decapitation strike which he considered tyrannicide, aimed at the Government of England; by blowing up the King and the House of Lords with gunpowder during the State Opening of Parliament. The assassination of the King was to be the prelude to a popular uprising aimed at regime change, through which a Catholic monarch would be seated upon the English throne.