Begin with what happened
London suffered a devastating plague epidemic in 1665–1666. The National Archives teaching collection provides original documents and explains the uncertainty around the death toll, which may have exceeded 100,000.
The question is not whether the plague struck—it did—but whether a particular historical response might have produced a different result.
Read before redesigning
Examine one contemporary order or report. What did its author believe? What action was proposed? Who would have to carry it out, and who bore the cost?
Do not give seventeenth-century officials modern scientific knowledge without explicitly making that an additional fictional change. Nor should a narrative promise a precise reduced death toll without a defensible model and evidence.
A bounded counterfactual
Imagine a change in how one documented measure is administered or supported. Explain the likely practical obstacles and the information unavailable to those involved.
Present benefits as hypotheses, not established medical conclusions. This is a historical exercise, not advice for managing present-day disease.
Compare the evidence
Use a 1665 mortality bill in London Museum’s collection to discuss what records count and what they may miss.
End by identifying an uncertainty you cannot resolve. Avoid claiming that a less severe epidemic necessarily accelerates an Enlightenment, a colonial empire or an industrial revolution.
Editorial review
Reviewed on 26 September 2026. Fixed the misleading title, removed invented death-toll precision and modern medical assumptions, and added original-document teaching sources.