The Monymusk Reliquary is an eighth century Scottish reliquary made of wood and metal characterised by an Insular fusion of Gaelic and Pictish design and Anglo-Saxon metalworking, probably by Ionan monks. It has been said to be the Brecbennoch of St. Columba (modern Gaelic Breac Bannoch or "embossed peaked-thing"), a sacred battle ensign of the Scottish army, used for saintly assistance, but is now thought not to be the object mentioned in historical records. Very few Insular reliquaries survive, although many are mentioned in contemporary records. It is an early example of the chasse or house-shaped reliquary, that became popular across Europe later in the Middle Ages, perhaps influenced by Insular styles. The Monymusk Reliquary is now empty.
It is characterised by a mixture of Pictish artistic designs and Irish artistic traditions (perhaps first brought to Scotland by Irish missionaries in the sixth century), fused with Anglo-Saxon metalworking techniques, an artistic movement now classified as Insular or Hiberno-Saxon art. The casket is wooden, but is covered with silver and copper-alloy. It was made around 750, probably by Ionan monks. It shows a combination of the Pictish and Insular styles which appear in manuscripts such as the Lindisfarne Gospels (c. 715 AD). The silver plates on the front and lid of the casket are decorated with beasts leaping and twisting, and biting at their tails on a spotted field, characteristic of animal style in Celtic art.