The analysis of unsmelted pieces of ore and slag found during archaeological excavations between 1981 and 1985 at Düna (near Osterode) in the South Harz indicates mining activity at the Rammelsberg in the 3rd century AD.
The King had discovered a cross in an oak and saw this miracle as a sign of victory, on the eve of a day where a battle against the Moors took place, according to what Rammelsberg writes.