French religious and political writer. Reluctantly, he was ordained in 1816. In 1818 he published the first volume of his Essai sur l'indifférence en matière de religion. In this he developed the principle of authority, which he equated with the ‘raison générale’ or ‘sens commun’, and maintained that the individual is dependent on the community for his knowledge of the truth. Later volumes (1820–3) equated Catholic Christianity with the religion of the whole of humanity, denied the supernatural, and proclaimed subjects freed from their loyalty to temporal sovereigns when rulers refused to conform their conduct to Christian ideals. To combat the evils of the time he desired a theocracy, with the Pope as supreme leader of kings and peoples. The work was approved by Pope Leo XII, who possibly intended to make him a cardinal. Later Lamennais prophesied an impending revolution and demanded separation both of the Church and the educational system from the State, as well as freedom of the press. In the final issue of his newspaper L'Avenir, he called for the union of all freedom-loving people. Convinced that the Pope would put himself at the head of this crusade for freedom, he went to Rome in 1832 to defend his ideas before Gregory XVI, but they were condemned in the encyclical ‘Mirari vos’ (1832). His famous reply, Paroles d'un croyant (1834), which admitted the authority of the Church in matters of faith but denied it in the sphere of politics, was condemned in June 1834. Lamennais left the Church and all attempts to reconcile him failed. He was a forerunner of Modernism.