Which title did William Parker hold when he received the warning letter before the Gunpowder Plot?

William Parker held the title 4th Baron Monteagle when he received the warning letter before the Gunpowder Plot.

The barony of Monteagle was an English peerage title. Parker was a Catholic nobleman who had held public responsibilities despite the religious divisions of early Stuart England. The anonymous letter addressed to him advised that he avoid Parliament because a sudden blow was being prepared against the king.

Parker gave the letter to Robert Cecil, secretary of state and one of the government’s leading investigators. James I became convinced that the wording referred to explosives, and officials searched the rooms beneath the House of Lords. Their discovery of Guy Fawkes and the gunpowder exposed the conspiracy.

The title is sometimes confused with the names of other Tudor and Stuart peers involved in the investigation, especially Robert Cecil, who was later made Earl of Salisbury. Monteagle was the recipient of the warning, while Cecil handled it for the government.