Medicine

Some of his most important writing was produced while fleeing suspicious rulers or hiding from arrest, in an unusually direct autobiography rare for a medieval scholar.

Pasteur kept his laboratory notebooks sealed for a century, and when historians finally opened them they found a scientist who sometimes shaded the truth about his own discoveries.

Freud built an entire theory of the mind from case histories whose patients he sometimes treated with the same certainty he applied to his conclusions about them.

Plague pits in Siena were dug so deep the chronicler said dogs dragged out the dead, but nobody recording the disaster could say how many people the plague actually killed.

Genetic testing on teeth from medieval graves finally confirmed in 2010 what centuries of chroniclers had only described in symptoms, that a single bacterium caused a pandemic whose recurring waves lasted from the 1340s into the early nineteenth century.

More Russian soldiers died of disease than were ever killed in battle, and the nurse who became world-famous for treating them mattered less for what she cured than for what she made everyone else finally admit about military hospitals.

1863

Nobody called it a revolution until a century after it supposedly happened, which is one reason historians still argue about whether it was one.