Nordic Bronze Age objects. These valuable metals were all imported, primarily from Central Europe, but they were often crafted locally and the craftsmanship and metallurgy of the Nordic Bronze Age was of a high standard. The archaeological legacy also comprise locally of crafted wool and wooden objects and there are many tumuli and rock carving sites from this period, but no written language existed in the Nordic countries during the Bronze Age. The rock carvings have been dated through comparison with depicted artifacts, for example bronze axes and swords. There are also numerous Nordic Stone Age rock carvings, those of northern Scandinavia mostly
Bronze Age Europe includes lur horns, horned ceremonial helmets, sun discs, gold jewelry and some unexplained finds like the bronze "gong" from Balkåkra in Sweden. Some linguists believe that an early Indo-European language was introduced to the area probably around 2000 BC, which eventually became Proto-Germanic, the last common ancestor of the Germanic languages. This would fit with the apparently unbroken evolution of the Nordic Bronze Age into the most probably ethnolinguistically Germanic Pre-Roman Iron Age. The age is divided into the periods I-VI, according to Oscar Montelius. Period Montelius V, already belongs to the Iron Age in other regions. In Great Britain,