A conspiracy in English Reformation history, formed by Guy Fawkes and others, to blow up the English Parliament in London in 1605. Guy Fawkes and his co-conspirators were discovered and put to death. an attempt was made to incriminate the Catholic Church by arresting the Jesuit priests Greenway and Garnett, to whom the conspirators made their last confession. But the priests kept the seal of confession. Henry Garnett was executed in 1606. One effect of the plot was the passage of new drastic measures of persecution against Catholics.