The Centuries were a sideline that outgrew the shop. Nostradamus's working publications were almanacs: yearly pamphlets of weather, harvest and event predictions keyed to the calendar, a crowded and profitable genre in which he published annually from about 1550 until his death, and which made his name long before the Prophecies appeared.
The almanacs sold across France and beyond, were pirated, forged and answered, and drew both his clientele of noble consultants and the scorn of professional astrologers who checked his planetary arithmetic and found it wanting. The first edition of the Prophecies, issued at Lyon in 1555 with three hundred and fifty three quatrains, extended the almanac method past any calendar: undated verses, scrambled in order, dense with classical allusion, place names and ellipsis.
Later editions grew the collection toward a thousand quatrains, some appearing only after his death, and bibliographers still labour over which printings are authentic. The verses' durability is partly engineered: grammatical ambiguity, proper nouns that might be anagrams, and the absence of dates make the quatrains impossible to falsify and endlessly available for retrospective matching, and each European crisis since has duly produced its Nostradamus pamphlets, along with outright fabrications attached to his name. The court took him seriously in his lifetime; Catherine de' Medici summoned him to read her children's horoscopes, and he died comfortable, a bourgeois of Salon, which is not the usual end of prophets.