The Picts were the nation that held northern and eastern Scotland from late Roman times until the ninth century, when their kingdom merged with the kingdom of the Scots to form the medieval realm of Alba. They left no surviving language. They left no written history of their own. What they left was stone - thousands of carved standing stones bearing symbols, animals, and elaborate Christian iconography. Most Pictish carving is on flat-faced cross-slabs or memorial pillars. The St Andrews Sarcophagus is something else entirely: a fully sculpted stone box, built from a sandstone local to Fife, originally consisting of two side panels, two end panels, four corner pieces, and a roof slab. The roof is entirely missing. Most of one side and one end are gone. What survives is essentially L-shaped - about 177 centimeters long and 70 centimeters tall - and on its surviving long panel is some of the most sophisticated narrative sculpture in early medieval Europe.

Read the surviving side panel right to left. First, a figure breaks the jaws of a lion with his bare hands. Second, a mounted hunter charges with sword raised at a leaping lion. Third, a hunter on foot - armed with a spear, accompanied by a hunting dog - prepares to attack a wolf. Nineteenth-century scholars assumed the first two figures were the same person, and the iconography supports them: the lion-jaw breaker is the biblical David, the shepherd-king of Israel, whose feats against bears and lions in defense of his flock prefigured his triumphs as warrior and ruler. David imagery was royal imagery in the early medieval Christian world - Charlemagne would be called the New David, English and Frankish kings claimed his mantle, and a Pictish king commissioning a sarcophagus with David iconography was making a specific claim. He was a Christian king in the tradition of the great Christian kings, and he wanted the burial that proved it.

The question that scholars have not settled is whose burial. The leading candidate is Onuist, son of Wurguist - the Pictish king known in Latin as Óengus, who died in 761 after a long and aggressive reign. Onuist was a Christian, a builder of churches, an ally of the Northumbrian church, and powerful enough to make the David comparison plausible. The competing candidate is his predecessor Nechtan mac Der Ilei, who died in 732 - the king who famously aligned the Pictish church with Rome on the contested issue of how to calculate Easter, and brought stonemasons north from Northumbria to build him a church in the Roman style. Either king could have commissioned the sarcophagus. The carving belongs to the second half of the eighth century, which fits Onuist's reign more cleanly. But the body that occupied it might have been a later one entirely. Medieval reuse of high-status tombs was common.

The cathedral that sheltered the sarcophagus had been in use since the 1100s. In 1559, during the Scottish Reformation, reformers stripped St Andrews Cathedral of its altars and images, left it in ruins, and walked away. For centuries afterward, the local masons mined the abandoned stonework for new buildings in the town - which is how the sarcophagus came to be buried about six feet down in what had become a graveyard. The 1833 workmen pulled out the large fragments but the pieces sat unassembled for almost a century. Not until 1922 were the surviving components reunited and put on public display. Even now the sarcophagus is incomplete - the missing roof slab leaves the interior open, the missing side and end panels leave one corner of the box unfinished. What you see in the museum is partly an eighth-century masterpiece, partly a twentieth-century reconstruction, and partly an honest admission that some things, once broken, can only be put back together as much as they can be put back together.