Born in Paris, Garencières studied the prophecies of Nostradamus at an early age, and these had a lasting effect on him. He studied at the University of Caen, which he left with a Doctorate of Medicine in 1636. To avoid religious persecution, he moved to the University of Oxford during the 1640s, which finally granted him the same qualification in 1657.
During the Great Plague, Garencières claimed to have a secret cure, and that nineteen of the twenty patients he had attended had recovered. He wrote of his "discovery" in A mite cast into the treasury of the famous city of London, being a brief and methodical discourse of the nature, causes, symptomes, remedies and preservation from the plague, in this calamitous year, 1665, digested into aphorismes. This book proved highly popular, seeing at least three editions inside a year.
While considering himself a Catholic, Garencières was a harsh critic of Pope Clement VIII, writing the endword to a work of 1670 entitled The famous conclave: wherein Clement VIII was elected Pope, with the intrigues and cunning devices of that ecclesiastical assembly: faithfully translated out of an Italian manuscript found in one of the cardinals studies after his death.
In 1672, Garencières was the first to translate Nostradamus into English, creating the bilingual text The true prophecies or prognostications of Michel Nostradamus. That year, he also wrote The Admirable Virtues, And Wonderful Effects Of The True And Genuine Tincture Of Coral, In Physick. Soon afterwards, he met Thomas Britton, with whom he shared a love of the esoteric. Britton designed him a mobile laboratory.
- The Royal College of Physicians suggest 1613 - 1677.
- A. Wear, Knowledge and Practice in English Medicine, 1550-1680
- Honey Vs. Sugar Archived 2013-01-25 at archive.today
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- Lance Library Catalog
- Robert H. Skaife, The Register of Marriages in York Minster, 1681 to 1762 Archived 2010-10-17 at the Wayback Machine
- Admissions to the Freedom of York 1-15 George II (1727-42)