Sir Rory Mor's Horn is a drinking horn, one of several heirlooms of the MacLeods of Dunvegan, chiefs of Clan MacLeod. Clan custom is that each successive chief is to drink a full measure of the horn in wine to prove his manhood.[1] The artwork on the horn has been dated to the 16th century, and by some as far back as the 10th century. The MacLeod chiefs have several other notable heirlooms kept at Dunvegan Castle, such as the Fairy Flag and the Dunvegan Cup (pictured right).