In 1655 Monck received a letter from the future Charles II, a copy of which he at once sent to the Lord Protector Oliver Cromwell, who is said to have written to Monck in 1657: "There be that tell me that there is a certain cunning fellow in Scotland called George Monck, who is said to lye in wait there to introduce Charles Stuart; I pray you, use your diligence to apprehend him, and send him up to me." Monck's personal relations with Cromwell were those of sincere friendship on both sides.