A royal letter of protection issued by King Henry III of England to Magnus, King of Mann, on 21 April 1255 (Easter), following Magnus's investiture with a military belt. The document commands all bailiffs and subjects not to receive Harald son of Gothred, Ivar, and their accomplices, who murdered Reginald, Magnus's brother and former King of Mann. This source illustrates early Anglo-Manx relations, succession disputes, and the feudal bonds between the English Crown and the Kings of Mann.