Passage: In 1604 Fawkes became involved with a small group of English Catholics, led by Robert Catesby, who planned to assassinate the Protestant King James and replace him with his daughter, third in the line of succession, Princess Elizabeth.  Fawkes was described by the Jesuit priest and former school friend Oswald Tesimond as "pleasant of approach and cheerful of manner, opposed to quarrels and strife ... loyal to his friends".  Tesimond also claimed Fawkes was "a man highly skilled in matters of war", and that it was this mixture of piety and professionalism that endeared him to his fellow conspirators.  The author Antonia Fraser describes Fawkes as "a tall, powerfully built man, with thick reddish-brown hair, a flowing moustache in the tradition of the time, and a bushy reddish-brown beard", and that he was "a man of action ... capable of intelligent argument as well as physical endurance, somewhat to the surprise of his enemies."The first meeting of the five central conspirators took place on Sunday 20 May 1604, at an inn called the Duck and Drake, in the fashionable Strand district of London.  Catesby had already proposed at an earlier meeting with Thomas Wintour and John Wright to kill the King and his government by blowing up "the Parliament House with gunpowder".  Wintour, who at first objected to the plan, was convinced by Catesby to travel to the continent to seek help.  Wintour met with the Constable of Castile, the exiled Welsh spy Hugh Owen, and Sir William Stanley, who said that Catesby would receive no support from Spain.  Owen did, however, introduce Wintour to Fawkes, who had by then been away from England for many years, and thus was largely unknown in the country.  Wintour and Fawkes were contemporaries; each was militant, and had first-hand experience of the unwillingness of the Spaniards to help.  Wintour told Fawkes of their plan to "doe some whatt in Ingland if the pece with Spaine healped us nott", and thus in April 1604 the two men returned to England.  Wintour's news did not surprise...

Question: Robert Catesby led what group of people?
English Catholics