The Mysteries of Free Masonry Containing All the Degrees of the Order Conferred in a Master's Lodge

William Morgan (1774 – c. 1826) was a resident of Batavia, New York, whose disappearance and presumed murder in 1826 ignited a powerful movement against the Freemasons, a fraternal society that had become influential in the United States. After Morgan announced his intention to publish a book exposing Freemasonry's secrets, he was arrested on trumped-up charges. He disappeared soon after, and was believed to have been kidnapped and killed by Masons from western New York.
The allegations surrounding Morgan's disappearance and presumed death sparked a public outcry and inspired Thurlow Weed and others to harness the discontent by founding the new Anti-Masonic Party in opposition to President Andrew Jackson's Democrats. It ran a presidential candidate in 1832 but was nearly defunct by 1835.