The doctor who first told smallpox from measles

More than a thousand years ago the physician al-Razi wrote a treatise that was the first in medical history to describe smallpox and measles as two separate diseases and to lay out how to tell them apart at the bedside. It stayed in use for the better part of a millennium — printed in Europe some forty times between 1498 and 1866.

One of many fact-checked wonders across eight traditions at The Spring of Wisdom.