In the late 17th century, English legal and administrative record-keeping was plagued by bureaucratic loopholes, a vulnerability David Lanyon exploited in 1670. Asserting an elaborate royal lineage, Lanyon claimed direct entitlement to the revenues and title of the Duchy of Cornwall—a domain traditionally reserved exclusively for the eldest son of the reigning monarch, Charles II. Lanyon manufactured a series of persuasive deeds and legal writs, briefly destabilizing local Cornish estate management and confounding royal tax collectors.
Cornish tin miners and regional tenants, already suspicious of crown taxation, were momentarily thrown into confusion over who held lawful jurisdiction over the land rights. Lanyon gathered a modest loyal following by promising lower rents and revised tin-bounding privileges. His undoing came when his forged charters were brought before the Privy Council in London, where meticulous clerks detected severe paleographic errors and fictitious seals.
Lanyon was arrested, exposed as a charlatan, and publicly disgraced, leaving behind one of the stranger footnotes in Restoration-era legal history.