Charles de Mornay, was a Swedish court official, diplomat and royal favorite. He was the central figure of the Mornay plot of 1574. Charles de Mornay was a French nobleman and HuguenotCalvinist. He served in the French troops in Scotland from 1547-1550. Between 1557 and 1559, he served as Swedish envoy to Poland, Denmark and England, during the marriage negotiations between queen Elizabeth of England and Eric XIV of Sweden. He was a favorite of Eric XIV, was an envoy to France and Scotland in 1561-62 during the negotiations of a marriage between Eric XIV and Mary Stuart, served as the king's adviser and member of the royal council, and served as a military commander in the Northern Seven Years' War. He was a prisoner in Denmark 1566-71, and was invited to return to the royal council by John III of Sweden. In the autumn of 1573, a plot was prepared to assassinate John III. The plot was led by Charles de Mornay, who was in contact with Christina of Denmark and the French ambassador in Copenhagen Charles Dancay. John III was to be killed during a swords dance performed by Scottish mercenaries at the party which was to be given in October that year before the Scottish mercenaries departure to the Baltic. After the assassination, the king's brother Duke Charles was to be placed upon the throne. Charles de Mornay, who had previously been the favorite of Eric XIV, promised that he knew the location of Eric's alleged hiddengold reserve, which he would reveal after the coup in exchange for better conditions for Eric in prison. However, the plot did not materialize as de Mornay lost his nerve and never gave the sign to the mercenaries to take action. In September 1574, the plot was revealed and Charles de Mornay was arrested, interrogated and executed. It was never made clear who participated in the plot. However, it is noted, that the suspected conspirators Hogenskild Bielke, Gustaf Banér and Pontus De la Gardie, often gathered at meetings in the apartment of Princess Elizabeth of Sweden, meetings where Princess Cecilia of Sweden had also frequently been seen, and the two sisters and their brother Charles were somewhat compromised though they were never accused. Charles de Mornay also revealed, that one of the things which were agreed upon by the conspirators was to raise the dowry of Elizabeth from 100,000 to 150,000, so to make it possible for her to make a marriage of higher status. It is noted, that the marriage between Elizabeth and Henry III of France, which was officially suggested in 1574, could have been informally suggested through Charles already the year before, and that the French ambassador had expressed himself impressed by everything regarding Elizabeth with the exception of her dowry.
