the reign of William I and was again depicted on seals used during the late thirteenth century; including on one particular example used by the Guardians of Scotland, dated 1286. Use of a simplified symbol associated with Saint Andrew, the saltire, has its origins in the late fourteenth century; the Parliament of Scotland decreed in 1385 that Scottish soldiers should wear a white Saint Andrew's Cross on their person, both in front and behind, for the purpose of identification. Use of a blue background for the Saint Andrew's Cross is said to date from at least the fifteenth century. The earliest reference to the Saint Andrew's Cross as a flag is to be found in the Vienna Book of Hours, circa 1503. Notes Medieval Scotland Middle Ages by country