The Gunpowder Plot, which King James described to Parliament in late 1605 as an attempt by Roman Catholics to destroy both the place and the persons associated with the passage of “cruell Lawes (as they say) … against their Religion,” has been controversial ever since James announced its discovery. Though the plotters evidently considered themselves loyal Roman Catholics, the provincial of the Jesuits in England, Henry Garnet, who knew most of them well, disavowed any connection with their activities and denied having given them moral support. Beginning in the middle of the seventeenth century, a theory was advanced, which still has some proponents, that the plot was as much the work of the English government as it was of those who were accused of treason and had as its object, not the restitution of Roman Catholicism in England, but its final extirpation. Recent investigations of the plot, especially of its ideological context, suggest that the attempted destruction of the central government was a serious threat by a handful of discontented men and could have caused immense, though unpredictable, changes in British society. It grew out of a long period of hostility between the see of Rome and the English government.

After the discovery of the Gunpowder Plot, King James modified the conciliatory policy towards his Roman Catholic subjects that he had followed earlier in his reign in England.