stephen greenblatt acknowledges the convention that the "equivocator" arriving at the gate of hell in the porter's speech in "macbeth" is a reference to the jesuit father henry garnet, who had been executed in 1606. he argues that shakespeare probably included the allusion for the sake of topicality, trusting that his audience would have heard of garnet's pamphlet on equivocation, and not from any hidden sympathy for the man or his cause – indeed the portrait is not a sympathetic one. literary editor bishop warburton declared that in the mind of jacobean playgoers the policy of equivocation, adopted as an official doctrine of the jesuits, would have been a direct reminder of catholic treason in the "gunpowder plot". shakespeare may have also been aware of the "equivocation" concept which appeared as the subject of a 1583 tract by queen elizabeth's chief councillor lord burghley, and the 1584 "doctrine of equivocation" by the spanish prelate martin azpilcueta that was disseminated across europe and into england in the 1590s.