Canute IV of Denmark, grandnephew of Canute the Great, considered crown of England to be rightfully his and, therefore, regarded William the Conqueror as an usurper. In 1085, with the support of his father-in-law Count Robert of Flanders and of Olaf III of Norway, he planned an invasion of England but it was never carried out because he was worried with the threat of Emperor Henry IV, with whom both Denmark and Flanders were in unfriendly terms. Before the fleet could reassemble, a peasant revolt occurred and he was killed. What if he had ignored the threat of Emperor Henry IV and carried out the invasion of England? Would the invasion succeed or fail? Would Emperor Henry IV have invaded Denmark, while Canute IV was away?