Which infamous European traitor was known as "the last person to enter Parliament with honest intentions"?

The story behind the answer

Guy Fawkes is the correct answer because he was the Gunpowder Plot conspirator discovered on the night of November 4–5, 1605, guarding barrels of gunpowder beneath the House of Lords. The quip that he was “the last person to enter Parliament with honest intentions” is a dark joke: unlike politicians’ murky motives, F