The theory that metallurgy was imported into Europe from the Near East has been practically ruled out. A second hypothesis, that there were two main points of origin of metallurgy in Europe, in southern Spain and in West Bulgaria, is also doubtful due to the existence of sites outside the centers of diffusion where metallurgy was known simultaneously with, or before, those in the ‘original’ nuclei, such as Brixlegg (Tyrol, Austria), while sites closer to the supposed origins of metallurgy, such as in the north of Spain, show fewer metal artifacts than sites in the south and practically no evidence of production.
Currently, the general opinion is that the development of metallurgy took place independently in different places, at different times, with various techniques. One fact that supports this interpretation is that, although the final products (beads, rings, sickles, swords, axes, etc.) are quite similar throughout Europe, the method of production is not. Thus the use of crucibles was the technique utilized in the south of Spain, whereas central Europe employed a slagging process, but Cabrierés (France) used a primitive oxidizing non-slagging process, while in the British Isles the absence of debris, slag or ceramic suggests another technique.
Consequently, the way in which metallurgy was initiated differs considerably depending on the region. There are areas in which copper seems to play a crucial role (i.e., the Balkans), whereas other areas show no interest in it at all. Then there are societies that use copper artifacts, but do not practice metallurgy, and there are other ones that fully adopt some of the cultural innovations but ignore the rest. One example of the latter is Basque country in northern Spain, where splendid large dolmens are present along the Ebro river, but metal is rather infrequent, and when it does appear between the trapping, it is more often bronze or arsenical copper than copper. According to radiocarbon dating, the Pre-Bell Beaker Chalcolithic with copper metallurgy began on the Iberian Peninsula in the last third of the IV millennium cal. BC, in the Northern Iberian Plateau in 3000 cal. BC and the Bell Beaker Chalcolithic appeared around 2500 cal. BC.