Popish Plot
From BiblePortal Wikipedia
Cyclopedia of Biblical, Theological and Ecclesiastical Literature [1]
the name given to an imaginary plot on the part of the Roman Catholics in England during the reign of Charles II. the object of which was believed to be a general massacre of the Protestants. (See Titus Oates).
The Nuttall Encyclopedia [2]
An imaginary plot devised by Titus Oates ( q. v .) on the part of the Roman Catholics in Charles II.'s reign; in the alleged connection a number of innocent people lost their lives.