Gunpowder Plot under King James had faded, leaving many English Catholics disappointed. His fellow plotters were John and Christopher Wright, Robert and Thomas Wintour, Thomas Percy, Guy Fawkes, Robert Keyes, Thomas Bates, John Grant, Ambrose Rookwood, Sir Everard Digby and Francis Tresham. Fawkes, who had 10 years of military experience fighting in the Spanish Netherlands in the failed suppression of the Dutch Revolt, was given charge of the explosives. The plot was revealed to the authorities in an anonymous letter sent to William Parker, 4th Baron Monteagle, on 26 October 1605. During a search of the House of Lords at about midnight
Ambrose Rookwood name was among the list of suspects drawn up by the Lord Chief Justice. The fugitives continued on to Dunchurch, where they met the recently recruited conspirator Everard Digby, with his hunting party. The next day the group stole horses from Warwick Castle, although with his fine cortège, Rookwood avoided the town. They then collected stored weapons from Norbrook, and continued on to Huddington. The party tried in vain to expand their number, but were shunned; no one was prepared to risk being labelled a traitor. Father Garnet, contacted at Coughton Court by Bates, wrote Catesby a letter in which