When Otto III (980-1002) came to the throne of Germany in 983, he was only three years old. Unusually, his grandmother Adelheid, the widow of Otto I 'the Great', acted as his regent, and a coinage was issued in both their names. The design was loosely based on earlier coins issued within the old Frankish empire which showed a classical temple, but the design was 'modernized' to show a contemporary German wooden church. The majority of Otto III's coins were minted at Goslar in Saxony. This reflected the discovery of silver nearby at Rammelsberg in the Harz mountains, earlier in the tenth century. From the 960s to the late eleventh century there was a huge output of silver from the Rammelsberg mines. Initially this fed the German coinage, but it seems likely that much of the coinage of northern Europe was actually produced from German silver.