The conspiracy of Amboise (1560; see Amboise, conspiracy of) during the reign of King Francis II inflamed both Roman Catholic and Protestant sentiment. This, along with political rivalry, particularly among the Bourbons and the Guises, precipitated the Wars of Religion (1562–98; see Religion, Wars of). Despite such heavy blows to the Huguenots as the massacre of Saint Bartholomew's Day (1572), the formation of the Catholic League (see League), and the intervention of Spain (1589–98) against the Protestant heir to the throne, the Bourbon Henry IV, the Protestants were ultimately victorious. Their success was due largely to their unity under such admirable leaders as Louis I de Condé (see under Condé, family), Gaspard de Coligny, Jeanne d'Albret, and her son, Henry IV.
In 1598, Henry IV, by issuing the Edict of Nantes (see Nantes, Edict of), established Protestantism in 200 towns, proclaimed freedom of worship, and allowed substantial political independence. During the next 50 years, more and more skilled artisans and members of the bourgeoisie became Huguenots, who thus constituted one of the most industrious and economically advanced elements in French society.