The Neupotz Hoard (the 'Barbarian Treasure')

For thirty years, from 1967 to 1997, the grab of a floating gravel dredger working a flooded pit near Neupotz, between Karlsruhe and Speyer, kept bringing up Roman metalwork from eight to twelve metres down. Piece by piece it added up to the largest Roman metal hoard found in Europe: 1,062 objects weighing more than 700 kg. The gravel layer that held it had been the bed of a meandering main channel of the Rhine in the third century.

Hardly anything here is precious in the usual sense. About 513 kg is iron, 203 kg copper alloy and only about 10 kg silver. There are four great bronze cauldrons that had been used as containers for smaller vessels, stacks of cooking pots, pans, jugs and sieves, silver cups and dishes, carpenters' and farmers' tools, padlocks and the iron fittings of goods wagons. Several vessels carry dedications, showing that shrines were stripped as well as kitchens. Some silver had been chopped up before it reached the river, valued for its weight, not its craftsmanship.

Most chilling are the fetters: ankle rings and manacles of a kind that could only have been meant for people. They do not prove that prisoners drowned at Neupotz, since they lay among the loot, but they fit the inscription on the Augsburg victory altar, which records thousands of Italian captives freed from raiders in 260.

The 39 coins end with an issue of the emperor Gallienus of 258-259. A worn coin of Probus from the 270s was once taken to date the hoard later, but it was picked up separately from a spoil heap and is now generally thought not to belong. The usual reading ties the hoard to 259/260, when Germanic war bands, probably Alamanni, broke through the Limes and plundered deep into Gaul. Returning home heavily laden, one group seems to have lost a wagon train or boats while crossing the Rhine, perhaps under attack from Roman river patrols, and the booty sank.

Neupotz is one of eighteen dredged hoards of the third century from the stretch of the Rhine between Seltz and Mannheim, including a similar find at nearby Hagenbach. Together they show what raiders wanted from the Roman provinces: metal of any kind, tools and the skills that went with them. The dredge also brought up a few prehistoric weapons and vessels and about 21 medieval objects, a reminder that a river bottom is not a sealed find.

The hoard belongs to the owners of the gravel works. After a major exhibition at the Historical Museum of the Palatinate in Speyer in 2006, they lent it in 2016 to the Museum für Vor- und Frühgeschichte in Berlin, which displays a selection in the Neues Museum beside the Xanten Boy, another Roman bronze lost in the Rhine.