Michel de Nostredame was born at Saint-Remy-de-Provence in December 1503, into a family of recent converts from Judaism, his grandfather, a grain and money dealer at Avignon, was baptised around 1455-60 and took the name Pierre de Nostredame.
The medical career is less impressive than the legend. He entered the university of Montpellier in 1529 and was expelled: the register survives, and the grounds were that he had worked as an apothecary, a manual trade barred by the statutes, and that he had disparaged physicians. The student procurator who struck him out was Guillaume Rondelet, later a distinguished naturalist. He never held a medical doctorate. He did practise, and his work during plague outbreaks was real and dangerous, but the standard description of him as a qualified physician of the French court overstates the qualification.
The Prophecies began in 1555 at Lyon with 353 quatrains, and grew to nearly a thousand in later editions. Peter Lemesurier's documentary work established how they were made, and the method is not what readers assume. The quatrains are largely retrospective: Nostradamus worked from earlier prophetic compilations, the Mirabilis Liber of 1522 above all, from Livy, Plutarch and collections of portents, and generated future events by comparative horoscopy, matching the planetary configurations of coming years to those of recorded past events and predicting that something similar would recur. The obscurity that permits centuries of reinterpretation is a property of the method rather than a veil over specific foreknowledge.
Nostradamus rejected the label of prophet himself, on the grounds that prophecy proper comes by divine inspiration, and described his work as astrological judgement. His readers have overruled him on that for four hundred and fifty years.