In 1670, King Charles II of England executed one of the most audacious backroom deals in royal history. Desperate for financial independence from a reluctant and suspicious English Parliament, Charles turned to his cousin, King Louis XIV of France. The resulting Secret Treaty of Dover was a masterclass in geopolitical deception.
Under its terms, Charles pledged to assist France in its military campaign against the Dutch Republic. Far more controversially, Charles agreed to publicly convert to Roman Catholicism—a deeply taboo move in Protestant England—at an undisclosed future date. In return, Louis XIV promised Charles a massive annual subsidy of 200,000 pounds, as well as 6,000 French troops to quell any domestic rebellion that his conversion might trigger.
To keep the English public and Protestant members of his own cabinet in the dark, a fake treaty containing only the military alliance against the Dutch was drafted and signed by unaware ministers. The actual secret treaty, containing the religious clauses and monetary payoffs, was known only to a tight inner circle of Catholic advisers. While Charles took the French funds to finance his court and foreign policy, he shrewdly postponed his public conversion until his deathbed in 1685.
The treaty remained undisclosed for decades, standing as a chilling example of a monarch secretly taking money from a foreign power to circumvent the constitutional limits imposed by his own parliament.