Nature's Evil

But the archaeologist V. Gordon Childe characterised the Iron Age as a time of democracy and monotheism. The use of iron weapons enabled the overthrow of the priestly elites; exchanging iron tools for farm products improved the life of the peasants. As it happened, the change of the resource platform was defined by the technical progress that had created a cheaper and abundant alternative. Throughout the civilised world, from India to Spain, the transition from bronze to iron was accompanied by the destruction of towns, the growth of violence and the decline of written culture. The magnificent palaces and trading towns of the Middle East disappeared. Archaeologists detect signs of the catastrophe in the deterioration of pottery and in the mass migration from coastal areas to the hilltops where cattle herders could protect themselves from pirates. It was a Time of Troubles; centuries passed before the peoples of Greece and Palestine could find new paths of cultural development. Then the Axial Age began, with its mass religion, written law and metal coins. 4

The success of the Hittites and the ‘people from the sea’ demonstrated that their iron weapons were at least as good as bronze ones, and probably cheaper. But the early methods of processing iron are still a mystery. The temperature at which mined iron melts has not changed to this day; it is impossible to achieve it in a furnace fuelled by wood. According to one theory, the ‘people from the sea’ used bog iron, which they brought from the Scythian steppes further to the north; using charcoal to heat the furnace, they were able to forge blades from this ore. Another theory claims that the Hittites forged weapons using ore with a high nickel content, which produced something like a steel alloy; in Anatolia there are deposits of this ore. According to a third hypothesis, the Hittites combined the carburisation of metal with its ‘tempering’. 5 Burning crushed iron ore with a large quantity of charcoal, they rapidly quenched the alloy in cold water. The alloy crystallises into a sturdy, malleable material, discovered anew by the German engineer Adolph Martens in 1902; this material was named Martensite.

The mysterious Hittites did not pass on their secret to descendants. The later armourers alternated folded layers of forged iron and tempered steel – the resulting sandwiches were lighter and sharper. Metallurgy is an art. The physical changes that occur in fibres are simpler and more predictable than the chemical reactions produced when various substances are heated and combined, such as oxidation, carburation or cupellation. Acquired through millennia of trial and error, empirical knowledge was secret. Every generation of miners and smiths had to learn their trade: starting his apprenticeship as a child, the pupil found himself completely under the power of his master. A rare and profitable profession passed down from father to son; childless blacksmiths (and there were many) easily found apprentices.

In peacetime, Rome depended more on brick and wood than on metal. But every Roman legion used hundreds of tons of iron for defensive and attack weapons. The further the borders of this empire stretched in the search for metal, the more arms, forts and metal it needed. The Roman mines were worked by slaves; many of them, however, were paid for their work and some became masters or managers. The smelting and forging depended on firewood, and the advantage of the north was evident. Mines in the Alps produced iron with a high manganese content; something akin to steel was forged from this ore, although the temperature wasn’t high enough for casting. In their battles with the Roman legions, the barbarians used long, masterfully forged iron swords. Visigoths and Vikings made excellent weapons, strengthening bog iron with magical practices harking back to the cult of the dead. Throughout Scandinavia, archaeologists have dug up forges in which they find the bones of humans and large animals such as elk and bear. With faith in their magic powers, blacksmiths forged bog iron with powdered bones to make sturdy swords. Experiments have shown that, with a limited supply of oxygen, bone meal carburises iron, creating a coating of sturdy, stainless steel.