Nicolas Flamel

The most famous alchemist in history almost certainly wasn't one.

Flamel was a real 14th-century Parisian — a manuscript scribe who, with his wife Pernelle, ran a successful copying shop and acquired enough property that streets in Paris are still named after them. He left charitable bequests funding hospitals, churches, and tomb stones. He left no alchemical writings of his own. Every text attributed to him appeared more than 200 years after his death, in 17th-century Paris, when publishers needed a sympathetic alchemist legend. The real estate empire was real. The transmutation career was retconned by the printing industry.