The Gunpowder Treason Plot is the name of the Roman Catholic conspiracy to blow up Parliament including King James I, the queen, and his eldest son. The conspirators were zealous Roman Catholics angered by the King’s refusal to grant more religious toleration to Catholics. They hoped the confusion that would follow the murder of the king, his ministers, and the members of Parliament would provide an opportunity for the English Catholics to take over the country.

The authorities were tipped off by an anonymous letter. During a search of the House of Lords at about midnight on 4 November 1605, one of the conspirators was discovered guarding enough gunpowder to reduce the House of Lords to rubble — about 36 barrels. The attempt failed. The conspirators were executed.