CATESBY, ROBERT (1573-1605), English conspirator, son of Sir William Catesby of Lapworth, Warwick, prominent recusant, was born in 1573, and entered Gloucester hall (now Worcester college), Oxford, in 1586. In 1596 he was one of those arrested on suspicion during an illness of Queen Elizabeth. In 1601 he took part in the rebellion of Essex, was wounded in the fight and imprisoned, but finally pardoned on the payment of an enormous fine. In 1602 he despatched Thomas Winter and the Jesuit Tesimond alias Greenway to Spain to induce Philip III. to organize an invasion of England, and in 1603, after James's acces sion, he was named as an accomplice in the "Bye Plot." Exas perated by his personal misfortunes and by the repressive measures under which his co-religionists were suffering, he was now to be the chief instigator of the Gunpowder Plot. The idea seems first to have entered his mind in May, 1603. About the middle of Jan. 1604 he imparted his scheme of blowing up the Parliament House to his cousin Thomas Winter, subsequently taking in Guy Fawkes and several other conspirators. But his determination not to allow warning to be given to the Roman Catholic peers was the actual cause of the failure of the plot. A fatal mistake had been made in imparting the secret to Francis Tresham (q.v.), in order to secure his financial assistance ; and there is little doubt that he was the author of the celebrated letter to his brother-in-law, Lord Monteagle, which betrayed the conspiracy to the Govern ment on Oct. 26. On receiving the news, Catesby exhibited extraor dinary coolness; he refused to abandon the attempt, and his confidence was strengthened by Fawkes's report that nothing in the cellar had been touched or tampered with. After the discovery of the conspiracy Catesby fled with his fellow-plotters, taking refuge ultimately at Holbeche, Staffs., where on the night of Nov. 8 he was overtaken and killed. He had married Catherine, daughter of Thomas Leigh of Stoneleigh, Warwick and left a son, Robert, who inherited that part of the family estate which had been settled on Catesby's mother and was untouched by the attain der. Robert is said to have married a daughter of Thomas Percy.
(See also GUNPOWDER PLOT.)