Charles de Mornay (1514 - 4 September 1574), was a Swedish court official, diplomat and royal favorite.
In 1559, he was the courtier who informed Eric about his the affair between princess Cecilia of Sweden and her brother-in-law, which resulted in the famous scandal known as the 'Vadstena Rumble'.
He 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.
However, the plot did not materialize as de Mornay lost his nerve and never gave the sign to the mercenaries to take action.
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.