Deep Time · Side by side

Two chapters, the same questions asked of both

Put two Deep Time chapters next to each other — their evidence base, the dating methods behind them, the live debates, and the questions still open.

Documented753 BCE – 476 CE

Rome

Engineering, law, and the administrative record of a Mediterranean empire.

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Documented2000 BCE – 1500 CE

Maya

A fully deciphered script, precise astronomy, and a still-contested collapse.

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The evidence base

Standing architecture, an enormous inscription corpus, legal texts, coinage, historical narratives, and preserved sites such as Pompeii and Herculaneum.

A deciphered hieroglyphic script, dated monuments, four surviving codices, lidar-mapped settlement, and continuing Maya communities.

How we know
MethodWhat it constrains
Materials science on ancient concreteCore samples from Roman marine and structural concreteIdentifies mineral reactions behind durability. It does not recover the original recipe as written.
Epigraphy and numismaticsInscriptions, milestones and dated coin issuesAnchors chronology and traces official messaging across the provinces.
Excavation of catastrophically preserved sitesPompeii, Herculaneum and their organic remainsPreserves a single moment in exceptional detail. That moment is not typical of the whole empire.
MethodWhat it constrains
Epigraphic deciphermentCarved stelae, lintels and painted ceramicsYields dynastic history in the rulers' own terms — which is court history, with its own agenda.
Lidar landscape surveyAirborne laser returns under forest canopyMaps structures and field systems at scale. Dating still requires ground excavation.
Palaeoclimate reconstructionLake sediment and speleothem records from the lowlandsDocuments drought intervals overlapping the Classic decline.
Where specialists disagree
  • Why did the western empire fall?

    Fiscal strain, military reorganisation, migration pressure, plague and climate all have serious advocates.

  • How large was the Roman economy?

    Proxy measures such as shipwreck counts and pollution in ice cores give ranges, not figures.

  • What drove the Classic-period collapse?

    Drought, warfare, soil exhaustion and political fragmentation interact differently by region.

  • How much of the codical tradition can be reconstructed?

    Four codices survive from what was clearly a much larger literature.

Still open
  • How much did climate variation shape imperial fortunes?
  • What did rural provincial life look like beyond the villa record?
  • How many texts remain unread in carbonised scroll form?
  • How were regional political networks structured between capitals?
  • How large were peak populations, now that lidar has changed the baseline?
  • How much surviving text remains unexcavated or unreadable?