Why did the Bronze Age civilisations collapse?

The question

In the 13th century BC the eastern Mediterranean was a connected world. The Egyptian pharaohs, the Hittite kings of Anatolia, the rulers of Babylon and Assyria, the Mycenaean palaces of Greece and trading cities like Ugarit in Syria wrote letters to each other, exchanged gifts and princesses, and traded copper, tin, grain and luxury goods across the sea.

Within a few decades around 1200 BC, much of this disappeared. The Hittite empire vanished and its capital was abandoned. Ugarit was destroyed and never rebuilt. The Mycenaean palaces burned, and Greece lost the art of writing for about four centuries. Egypt survived, but weakened. In 1881 the French Egyptologist Gaston Maspero popularised a name for the invaders mentioned in Egyptian texts, an idea first suggested by Emmanuel de Rougé: the "Sea Peoples". The question of what really happened has been argued over ever since.

What we know

• Many cities across Greece, Anatolia, Cyprus and the Levant were destroyed or abandoned between the late 13th and the 12th century BC. How many, and how close together in time, is debated: recent reassessments find that some destructions were smaller than once thought and were spread over several decades.
• Egyptian inscriptions at the temple of Medinet Habu describe a great land and sea battle in the eighth year of Ramesses III, dated to about 1180–1175 BC, against a coalition of peoples who, the text says, had already crushed the lands to the north.
• The last letters of Ugarit describe enemy ships off the coast and a kingdom whose troops and fleet were elsewhere. The city fell soon after.
• Climate changed. Pollen in lake and sea sediments from the Levant and Cyprus shows a drier period around this time. In 2023 tree rings from Anatolian juniper wood revealed three consecutive years of severe drought around 1198–1196 BC, right when the Hittite state collapsed.
• Texts from the period mention famine: the Hittites asked Egypt and Ugarit urgently for grain.
• Many sites in the region lie on active faults, and some destructions show possible signs of earthquakes.
• Afterwards, some places recovered quickly in new forms. Iron gradually replaced bronze, and new states arose: the Phoenician cities, Israel, the Neo-Hittite kingdoms.

Main hypotheses

Invasion and migration

The "Sea Peoples" swept through the region, destroying cities. Few historians now see them as the main cause. They seem to have been partly a result of the crisis: displaced groups looking for land, not an army that came from nowhere.

Drought and famine

A long dry period ruined harvests, caused famine and pushed people to migrate. The evidence for drought is growing, but it was not the same everywhere, and its timing must match each destruction closely to explain it.

Earthquake storms

A sequence of large earthquakes over several decades may have struck many cities in turn. Critics point out that earthquakes rarely destroy a state permanently, and that it is hard to distinguish damage from an earthquake and from an attack.

Systems collapse

Perhaps no single cause was decisive. The palace economies were highly specialised and depended on each other: tin from far away, grain shipped across the sea, centralised control. Such a system could be efficient but fragile, and a combination of drought, unrest, raids and broken trade could bring it all down together, like a chain of dominoes.

What would settle it

• Precise dates for destructions and climate changes, site by site, from tree rings and radiocarbon, showing what came first.
• New written archives from the last years, like those of Ugarit, from other cities.
• Models of the Bronze Age economy that make testable predictions about which places should have fallen first and which should have survived.