Friday, 13 March 2009

Early civilisation, part 2: Metallurgy

The discovery of how to work metal, by definition, brought human beings out of the Stone Age.

The importance of metal technology was evident when nineteenth century Europeans devised the ‘three age’ system, proposing that early human societies could be classified into successive stages of Stone, Bronze and Iron. A division of the Stone Age into Old and New was later added, and in some places a Copper Age.[1]

This was a step forward for developing archaeology into a science, but if the terms were useful for Europe and the Mediterranean, they were less so for southern Africa and South America where bronze and iron were not discovered, or only in some places [2]. What’s more, the great disparities in the timing of certain technologies make the Ages of limited use as chronological terms. The Classic Maya civilisation had astronomy that outstripped that of medieval Europe, while still using Stone Age technology. When confronted with the uneveness of development of human culture, science must bend itself to reality, not the other way around.

Some metals, such as gold, copper, silver and tin can be found native, or ‘free’ (without mining), in the form of nuggets, and small metal objects appear at early farming sites and even during the Paleolithic.

Nugget of native copperNugget of native copper. Photo: Jonathan Zander

But prehistoric peoples had invented kilns with which to fire ceramic pots and figures, and probably tested all kinds of earth and stone to find the best materials. By accident and experiment, they found that pieces of naturally-occurring metal became liquid at high temperatures, then became solid again as it cooled. While warm, it was soft enough to be beaten into shapes. The most important metal in the run-up to the Urban Revolution was copper. By the 4th millenium BCE, the plough, which had previously been little more than a crooked branch, was not only harnessed to oxen but given a copper blade. The opening of the Gilgamesh epic, quoted in the previous article, gives us a sense of admiration of this material in its praise of Uruk: “See how its ramparts gleam like copper in the sun.”[3]

All sorts of new inventions were required to take advantage of metals. Copper and tin are relatively rare, and required mining if they were to be retrieved from inaccessible places. Kilns, bellows, tongs, crucibles and moulds were all needed. This explains why metallurgy could not become widespread before the Urban Revolution — it was only when a surplus of foodstuffs was being produced that full-time specialists were able to make these technical advances. The search for copper led to the discovery of gold, silver and the iron brought by meteorites. A further step forward was the discovery of smelting, which applies the intense heat of a kiln to extract copper and tin ores from rock. By heating copper and tin, specialist smiths found both could be combined to make an alloy which was harder than either, easy to cast, and gave a sharp edge to tools and weapons — bronze.

Bronze production appeared in Mesopotamia and Egypt around 3000 BCE; although it used to be assumed that metalworking radiated out from the Near East, archaeologists now believe it rose in a few centres independently, including the Balkans and the southern Iberian peninsula. The production of copper and bronze was developed independently in the Americas around 2000 BCE in the Andes.

Bronze was to be the dominant metal until the production of iron around the 12th century BCE, and even then remained in widespread use until about 500 BCE.

Whereas lead and copper are respectively rather soft and brittle, bronze proved an exceptional material for tools and weapons. A tool of flint or stone, once broken or blunted, must be discarded, whereas metal can be resharpened or even melted down to make a brand new object — even a more advanced one than before. This did not make stone tools obsolete by any means. Gordon Childe suggests that “it needed the special geographical conditions of an alluvial plain, where suitable stones were rare, to drive home the value of the new and more permanent material.”[4]

Beside these strictly practical uses, metals inevitably also became materials for art. Not only were they hardwearing and strong, and could be polished to a shiny lustre, they were malleable enough to be given any form. In Childe’s words:

The real superiority of metal is that it is fusible and can be cast. Fusibility confers upon copper some of the merits of potter’s clay. In working it the intelligent artificer is freed from the restrictions of size and shape imposed by bone or stone. A stone axe-head, a flint spear-point, or a bone harpoon can only be made by grinding, chipping, or cutting bits off the original piece. Molten copper is completely plastic, and will adapt itself to fill any desired form; it can be run into a mould of any shape and will assume, and on cooling retain, precisely the form outlined by the mould.[5]

With this material, artisans had a new freedom where their skills were the only limitations — objects could become more precise, more refined, and more exactly representative of their cultural wishes.

Akkadian bronze headHead of an Akkadian ruler believed to be King Sargon, bronze, c. 23rd–22nd century BCE.

This had modest beginnings, of course: in Çatalhöyük, copper and lead were shaped into pendants, rings and beads. Later, metal was used to create sophisticated art works — jewellery, musical instruments, ritual images, tomb offerings and portraits of kings. Royal graves have been one of the richest sources of ancient artworks. Excavating the remains of Ur in 1927, archaeologists discovered Sumerian objects dating back to around 2600 BCE, including a silver head of a lion and a lyre with a bull’s head of beaten gold. The single richest tomb was that of Puabi, believed to have been a queen of Ur, which was unspoiled by looters: the tomb yielded a golden head-dress and other items of jewellery.

Works such as these show that ancient society brought metalworking to a high degree of perfection. Renfrew and Bahn note:

By the late Bronze Age of the Aegean, for example, around 1500 BC, as wide a range of techniques was available for working with non-ferrous metals as was used in the Classical or early medieval periods. For instance, the techniques of working sheet metal were well understood, as were those of stamping, engraving, and repoussée working (work in relief executed with hand-controlled punches from the back of sheet metal). Filigree work (open work using wires and soldering) was developed by the 3rd millenium BC in the Near East, and granulation (the soldering of grains of metal to a background usually of the same metal) was used to achieve remarkable effects, notably by the Etruscans.[6]

The fruits of these skills were not conferred equally upon all the people of early civilisation. Metals were expensive to obtain and expensive in labour, and thus became symbols of prestige dominated by the ruling class. Personal ornaments, cups, dishes, figurines and other fine objects not only embellished the rich while alive but even accompanied them in death.

Mask of TutankhamunThe mask of Tutankhamun, c. 1323 BCE.

One of the most famous examples of this is of course the funerary mask worn by the mummy of Tutankhamun. Discovered in Tomb KV62 in the Valley of Kings, this mask was found inside three other sarcophagi, the inside one made of pure gold. The mask itself was placed over the head and shoulders of the dead pharaoh. Inlaid with lapis lazuli and coloured glass and weighing twenty-four pounds, it was made from gold sheets joined by heating and hammering. The selection of gold for sending someone to eternal life was not arbitrary, as gold has the property of being chemically inert — unlike copper, it does not react to other chemicals, which means that it retains its beauty and colour permanently. It is also highly malleable, which allows smiths to create gold leaf and finely worked jewellery. Most of the Mask seems to have been hammered from the reverse side, using the repoussée technique, from a single sheet of gold.

As remarkable as the craftsmanship involved in a work like this was the fact that civilisation was prepared to spend so much labour and treasure on an object that, they supposed, would never be seen again (it was up to tomb robbers to put the gold back into circulation). Such a huge expenditure of resources, not only for one individual, but a dead individual, shows the profound changes wrought on society and the role of artists by high levels of production. Tutankhamun was a minor Pharaoh, who came to the throne aged about nine, reigned for ten years, and was buried in a tomb built for someone else; nonetheless, his relatively small tomb was filled with thousands of items, many of them of precious metals. By contrast, none of the labouring population could expect mummification and masks of beaten gold — there’s no sign here of the egalitarianism of the hunter-gatherers.

Part of our understanding of the art of civilisation, therefore, depends upon the concept of class society.

[1] We owe the Three Age system to the Dane, Christian Jürgensen Thomsen, and the division of the Stone Age into old and new to Sir John Lubbock. Further archaeologists have made additional refinements.
[2] Strictly, almost every contemporary society is still in the Iron Age, as iron remains in use. But there comes a point when it stops being useful as an archaeological term.
[3] The Epic of Gilgamesh, in the translation by Stephen Mitchell.
[4] V. Gordon Childe, Man Makes Himself (1936).
[5] Ibid.
[6] Colin Renfrew and Paul Bahn, Archaeology: Theory, Method and Practice (5th ed., 2008).

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