Popish Plot

http://en.wikipedia.org/wiki/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 execution of at least 22 men and precipitated the Exclusion Bill Crisis.
http://en.wikipedia.org/wiki/Exclusion_Bill

Eventually Oates' intricate web of accusations fell apart, leading to his arrest and conviction for perjury.