Nostradamus published the first instalment of Les Propheties in Lyon in 1555 through the printer Mace Bonhomme: three complete Centuries and part of a fourth, 353 quatrains in all. A revised edition followed the same year, and a third, adding three further Centuries, in 1557. The full ten Centuries, roughly 942 quatrains, appeared only in 1568, two years after his death, in an edition carrying a dedicatory letter to King Henry II.
He explained his method in a preface addressed to his son Cesar, printed with the 1555 edition: the verses were deliberately obscured, he wrote, both to guard against a charge of sorcery in an age that burned people for less, and because plain language would let the unworthy grasp what he believed should be reserved for the discerning. The result mixes Provencal and Italian words into the French, borrows syntax from Latin, and leans on anagram and paraphrase rather than direct statement; a quatrain will name "Hister" rather than a country, or describe a figure by trade and bearing rather than by name.
That obscurity is structural, not incidental. Almost no quatrain fixes a year, and few name a place unambiguously, which is the feature that has let each generation of readers supply its own referent. Napoleon-era commentators read the Hister verses as Napoleon; twentieth century readers read the same lines as Adolf Hitler. Peter Lemesurier's study of the manuscript tradition traces how successive interpreters have treated the verses as addressed to their own moment, a pattern the text's built-in vagueness makes easy to repeat and hard to test.