Why the Bronze Age collapsed

In our first article from Issue 27, Patrick Fitzsimmons explains what really ended the Bronze Age.Over three thousand years ago, on a plain beside the Orontes River in Syria, two great armies clashed in what may at the time have been the most colossal battle ever seen: the Battle of Kadesh. The two combatants, the Egyptians and the Hittites, together put forward tens of thousands of soldiers and over five thousand chariots, making the number of combatants comparable to some smaller First World War battles, and quite likely bigger than Agincourt, Hastings, and Yorktown. It was also the first battle whose events can be reconstructed in detail, as Pharaoh Ramesses II afterwards commissioned elaborate stone reliefs depicting the battle as a monumental victory, which remain in temples dotted across modern Egypt to this day.The Egyptians and the Hittites were two of several great powers then dominant in the eastern Mediterranean. Others were the Assyrians, the Babylonians, and Mycenaean Greeks. All were bureaucratically complex societies, in some cases controlling territories of hundreds of miles, capable of mobilizing armies, extracting taxes, and completing ambitious infrastructural projects. But just a few centuries after the Battle of Kadesh, all had vanished or dwindled to a fraction of their former power.Pharaoh Ramesses II had elaborate carvings made depicting his military feats against the Hittites at the Battle of Kadesh in 1274 BC, at the time the largest military battle ever fought. Sixteen years later, the Egyptians and Hittites signed what is thought to be the oldest surviving peace treaty (right). Just a few centuries later, the two empires that clashed at Kadesh would be gone. Image credit: Wikimedia.The Bronze Age collapse – as this sudden disappearance of regional powers is known – is one of the great mysteries of ancient history. The usual explanation points to a series of catastrophes around 1200 BC: droughts, mysterious invaders called the Sea Peoples, famines, and internal revolts. But such explanations are insufficient as catastrophes like these often create political upheaval without permanently ending civilizations. The question is not why the Bronze Age empires fell, but why, after they fell, nothing like them returned for centuries. Why did it suddenly become so hard, seemingly, to build and sustain an empire?If you go to see Ramesses’s stone reliefs today, your tour guide might tell you that both sides at the Battle of Kadesh wielded bronze weapons, common for imperial armies of the time. Bronze is an alloy of copper and tin, and the tin in those bronze weapons would have had to have traveled thousands of miles from distant mines, perhaps in modern Afghanistan or in Western Europe. The difficulty involved in mining and transporting tin is one reason that access to bronze weaponry remained concentrated in military and elite institutions. The average citizen still largely relied on tools made of copper, stone, bone, or wood. But just a few centuries after Kadesh, ordinary Hittite and Egyptian farmers had access to a new material: iron.Because iron could be produced locally, imperial centers no longer had such a strong advantage over their subject peoples. The invention of iron weaponry meant the political equilibrium was forever changed.Today, we live in an era where access to the tools of violence has been exceptionally concentrated, allowing superpowers far larger than those of the late Bronze Age to reign largely unchallenged. But as military technology evolves, another age of upheaval may be approaching.The invention of bronze had already displaced an earlier metal: copper. The Copper Age began around 5000 BC and ran until around 3000 BC, when bronze weapons began appearing in the archaeological record. Copper was accessible enough and easy enough to work that it allowed early proto-states to reliably arm their warriors with something better than stone weaponry, which often chips or breaks under impact. Copper is a soft metal, hence its use in pipes and wiring today. But it generally won’t break, and though it does bend easily it can also be bent back into shape. This marginal benefit was enough to give groups with copper weapons a significant advantage.Humans made weapons out of stone for hundreds of thousands, perhaps millions, of years. But once we learned to use metals – copper, then bronze, iron, and steel – stone weapons were on borrowed time. These are excerpts from the Lienzo de Tlaxcala, a sixteenth-century manuscript painted by the Tlaxcalans, longtime rivals of the Aztecs, to record the conquest of Mexico by the Spanish. The Mesoamericans fought with weapons made from obsidian, a hard, jet-black stone that was very sharp but brittle. They were brutally outmatched by a European military armed with steel swords, gunpowder, and horses. Image credit: New Mexico History Museum.Copper-wielding groups pushed into surrounding communities who used stone tools, beginning a process of prehistoric political consolidation. We see an increase in the number of fortified settlements, rising inequality in the grave goods with which people were buried, suggesting deepening hierarchies, and complex smelting sites as far as sixty miles away from where copper was mined, suggesting increased economic specialization.Copper weapons were eventually made obsolete by the invention of bronze, made by combining copper and tin. Bronze is harder and stiffer, and will hold a sword’s edge for longer, which gave bronze-wielding groups a strong military advantage.The spread of bronze preceded a wave of imperial conquest across the eastern Mediterranean. The Annals of Hattusili I, a cuneiform tablet found in the 1950s, details the expansion of the Hittite empire from its core in central Turkey to the Aegean Sea in the west and the Euphrates in the east during the 1600s BC. While the tablet is royal propaganda, the Hittites evidently viewed their history as one of conquest over surrounding groups: the tablet boasts of foreign cities sacked and burned, with weeds sown on the sites where they once stood. Egypt also saw its territory grow to incorporate large parts of Nubia and the Levant at around this time. These military successes would not have been possible without bronze.Copper had come with a growth in social complexity and political consolidation as the metal required knowhow and social organization to mine, transport, anneal and smelt, and gave groups employing it an edge over stone users. Bronze entrenched this advantage due to a single geological fact: while copper had been somewhat rare, the tin required to transform it into bronze was even rarer.The major tin deposits accessible to Bronze Age peoples from 3000–1200 BC were in modern Afghanistan, France, Iberia, and Cornwall, in southwest England. Distinctive chemical features of individual deposits mean we can track just how far tin mined in these places spread. Tin with trace levels of indium, particular to the Cornish deposits, has been found in shipwrecks near Israel and southern France, showing that Cornish tin traveled for thousands of miles. Smaller deposits existed in Turkey, the Eastern Desert of Egypt, and Iran.The city-state of Mari in modern-day Syria acted as a tin hub, importing the metal from sources in the east and shipping it west up the Euphrates River. Texts from the eighteenth century BC record that Mari’s tin traveled over five hundred miles from a kingdom called Elam, which was itself another thousand miles from the Afghan mines that were its likely source. In addition to the distance and the difficult terrain, an ancient trader would have to worry about roaming bandits and aggressive foreign states along the way. Tin was extremely difficult for Bronze Age people to get hold of, making bronze weapons expensive.This had a profound political consequence: elites had a major advantage in accessing the tools of violence. While smaller city-states could also get their hands on bronze, larger and more complex empires could do so more reliably. It was easier for them to obtain supplies, secure trade links, create stockpiles and replace losses. A Bronze Age king could field and sustain an army that smaller forces simply could not match. Peripheral communities at the edges of empires might resist for a while, but maintaining a seriously competitive army over time required state capacity that smaller forces generally lacked.At the time of the Battle of Kadesh, the eastern Mediterranean and Near East were filled with competing great powers: the Hittites had conquered most of Anatolia, the Egyptians controlled an area that stretched down into Sudan, the Assyrians and Babylonians vied for dominance in Mesopotamia, and southern Greece was ruled by a constellation of principalities including Mycenae, Pylos, and Thebes. These were advanced, bureaucratically organized societies that extracted labor, taxes and tribute from subjects and surrounding peoples.Around 1200 BC, the system broke down. The archaeological record shows the imprint of bursts of violence before great empires disappeared. Greek palaces show ‘destruction layers’, archaeological evidence of burning, from a short period around this time. Similar scorch marks and scattered bones have been unearthed at Troy in a layer contemporary with the end of the Bronze Age.In Greece, the kingdoms that had ruled the mainland collapsed so completely that the ensuing centuries were termed the Greek Dark Ages. The Hittite Empire, which had matched Egypt at Kadesh, virtually vanished. A centuries-long record of clay tablets detailing the culture’s laws, rituals, and literature abruptly stops at around 1200 BC. Egypt itself survived, but shrank, losing its Levantine territories and never recovering its former reach or imperial power. Similarly, Assyria contracted back to its inland imperial capital, and Babylonia, shaken by the collapse of the 440-year-old Kassite ruling dynasty, barely managed to limp