All corrections
1
Claim
the big ones mostly peaked at around the same size: ~60-80M people.
Correction

Historical population estimates for major premodern empires vary much more widely than 60–80 million. Standard references list several of the largest preindustrial empires well above 80 million, including the Qing, Mughal, and Ming polities.

Full reasoning

This sentence presents a concrete empirical claim about what the data on large premodern empires show. But standard historical references do not show that the large ones "mostly" peaked around 60–80 million people.

A recent synthesis by Peter Turchin and Daniel Hoyer lists the 10 most populous societies in the entire preindustrial era as: Qing dynasty 334–348m, First British Empire 200–250m, Mughal Empire 110–150m, Ming dynasty 90–110m, Northern Song 60–100m, Yuan 60.5–85m, Tang 60–80m, Roman Dominate 40–70m, Western Han 57.6–60m, and Roman Principate 50–60m. In that table, only one entry is cleanly in the 60–80m band, while several of the biggest premodern empires are far above it.

Independent reference works point the same way:

  • Britannica says the Qing population grew from about 150 million to 450 million.
  • Britannica's history of the Ming says modern scholars estimate the population grew to well in excess of 100 million and perhaps nearly 150 million in the early 17th century.
  • A Cambridge University Press history of India says the Mughal population in 1700 may have been 100 million.

So while some major empires did fall near 60–80 million, the historical record does not support the broader statement that the big premodern empires mostly peaked there.

4 sources
Model: OPENAI_GPT_5 Prompt: v1.16.0