The Rye House Plot of 1683 was a plan to assassinate King Charles II of England and his brother (and heir to the throne) James, Duke of York. The royal party went from Westminster to Newmarket to see horse races and were expected to make the return journey on 1 April 1683, but because there was a major fire in Newmarket on 22 March (which destroyed half the town), the races were cancelled, and the King and the Duke returned to London early. As a result, the planned attack never took place.
Historians vary in their assessment of the degree to which details of the conspiracy were finalised. Whatever the state of the assassination plot, plans to mount a rebellion against the Stuart monarchy were being entertained by some opposition leaders in England. The government cracked down hard on those in a series of state trials, accompanied with repressive measures and widespread searches for arms. The plot presaged, and may have hastened, the 1685 Monmouth Rebellion and Argyll's Rising.