Popish Plot
The Popish Plot was a fictitious conspiracy concocted by Titus Oates that between 1678 and 1681 gripped the Kingdoms of England and Scotland in anti-Catholic hysteria. Oates alleged that there existed an extensive Catholic conspiracy to assassinate Charles II, accusations that led to the executions of at least 22 men and precipitated the Exclusion Bill Crisis. Eventually Oates' intricate web of accusations fell apart, leading to his arrest and conviction for perjury.
Background
Development of English anti-Catholicism
The fictitious Popish Plot must be understood against the background of the English Reformation and the subsequent development of a strong anti-Catholic sentiment among the mostly Protestant population of England.