During most of the Middle and Late Bronze Age, iron was present, albeit scarce. It was used for personal ornaments and small knives, for repairs on bronzes, and for bimetallic items. The Iron Age thus did not start with the first appearance of iron but rather at the stage when its distinct functional properties were being exploited and it began to supplant bronze in the production of tools and weapons. This occurred at different times in various parts of Europe, and the transition to the Iron Age is embedded in local cultural developments. The reasons why iron was adopted differed among regions, but generally a similar pattern was followed. After an introductory period, iron quickly supplanted bronze for the making of tools and weapons. It was at this stage that metal, in spite of the earlier presence of bronze tools, replaced stone, flint, and wood in agricultural production. New and more effective tools were developed during the last centuries bce, and subsistence production must have increased drastically. Along with these domestic changes, there were changes in the traditional routes of contact and trade. These routes had been established during the Bronze Age, and through them copper, tin, and other commodities had traveled throughout Europe. With the appearance of the rich Late Hallstatt communities of south-central Europe, the orientation of contact changed. The northern links were increasingly ignored, and trade became concentrated on, and dependent upon, commodities from the south. South and west-central Europe were now included in the periphery of the expanding Mediterranean civilization; and the previous network of contact was broken. In the rest of Europe, regional diversity increased, a tribalized landscape emerged, and new types of social organization developed. During the Iron Age, the roots of historic Europe were planted. Proto-urban settlements, hierarchical social orders, new ideological structures, and writing were parts of this picture. It was also a time during which the difference between the Mediterranean world and temperate Europe became even more pronounced and new degrees and forms of dependency developed in the sociopolitical systems. Social and economic developments Control over resources
The Metal Ages were periods of discovery, invention, and exploitation of various metals and metallurgical procedures. New elements were introduced into the societies, which played a role in their further development. In the later 5th and earlier 4th millennia bce, copper from easily worked surface deposits was used for relatively simple items in southeastern Europe and the Carpathian Basin. The Transylvanian copper ores were particularly important. For example, copper was extracted from the quarry at Varna, Bulg., about 4400 bce in an area near a rich Copper Age cemetery. After this initial exploitation, metal objects again became rare until they reappeared in the late 4th millennium bce. The reasons for this change are unknown but may in part relate to the depletion of surface ore deposits. At this early state, the technique of copper manufacture consisted of smelting in an open one-faced mold and hammering. Later, when copper of different compositions from deeper deposits was used, the properties of copper in combination with other metals were explored. The copper sulfide ores from these deep mines were more difficult to procure, since they relied on more sophisticated mining techniques and needed initial roasting before smelting. At the same time, they were more widely available than surface deposits, and there were sources in both central and western Europe—ores in Germany, Austria, and the Czech and Slovak Republics were exploited from the early 3rd millennium bce. This long initial phase of sporadic use of copper was finally replaced by a period of copper alloys, which began about 2500 bce in southeastern Europe, slightly later in the Aegean, and later still in Iberia. Bronze industries were widespread in Europe by 2300 bce, but copper-tin alloys were first used toward the end of the 3rd millennium, with renewal of the centres of metallurgical production in Austria, Germany, and neighbouring areas. The raw material needed was available only in a few regions, and tin, particularly restricted in its distribution, was found only in eastern Portugal, Sardinia, Tuscany, Cornwall, the Isles of Scilly, and the Bohemian Ore Mountains. The latter site, on the border between the Czech Republic and eastern Germany, was one of the rare instances of close proximity between copper and tin. This region, together with the copper areas of the Harz Mountains, the Alps, and central Slovakia, became one of the most important regions of the Early Bronze Age. With the progression of the Bronze Age, local metallurgical traditions developed throughout Europe, including areas lacking both tin and copper sources; but the chief metalworking centres continued to influence the material culture of larger areas. This was an important factor behind the trade and exchange network that came into existence.
The discovery of iron was most likely a by-product of bronze working, and much of the earliest iron use is not culturally distinct from the use of bronze. At its early stage, iron may have been monopolized and produced by those individuals or groups who controlled bronze. Iron, however, is different from bronze in many respects. It is found widely in Europe either as iron ore or as bog iron. To be usable, iron does not need alloying with other metals, and the demands are mainly the fuel and labour needed to smelt or roast the ore. This process involves high temperatures and skilled control of pyrotechnology. To produce a usable iron, the bloom must be hammered while red-hot to reduce the impurities and to change its internal structures. Only then can the shaping of the final object begin. Thus, the production of an iron object consists of several distinct stages, each different from those involved in bronze production.
Iron appeared in Romania about 1700 bce and in Greece shortly after. During the Middle and Late Bronze Age, it occurred infrequently except in Iberia, Britain, and some other parts of western Europe. The earliest iron was used for small knives, pins, and other personal objects and for repairs on bronze items. Only in Romania was iron used for heavy tools during the Bronze Age; toward the end of the Bronze Age, tools and some weapons made of iron appeared generally in Europe. With Ha C, iron swords were being made, and, in the following La Tène Period, iron had clearly become a material important in its own right, being used for a range of new functional items, including plowshares, carpentry tools, and nails. At this point it is likely that the previous monopolies on metal production and trade were severely challenged, and iron became a common material, produced and procured anywhere in Europe.
The intensity of metal use varied regionally, and the centres of innovation and wealth moved over time. During the Metal Ages the communities of Europe can be studied through their reaction to, and adoption of, their inventions. It is a phase in prehistory that raises cultural questions about the nature of innovation and of its consequences for society. Metal brought several important new items to the communities, but, more importantly, it changed the nature of society itself. The production of bronze was an important step in human history, indicating a point at which the limits imposed by natural materials were broken by human invention. The behavioral impact of this cannot be measured, but it was likely substantial. It may have altered attitudes to nature and created the activities that resulted in deep mining of metals and salt and caused experimentation with new materials, such as glass.