The Concordat of 1851 was an concordat between the Spanish government of Queen Isabella II and the Vatican. Although the concordat was signed on March 16, 1851, its terms were not implemented until 1855. The concordat remained in effect until it was repudiated by the Second Spanish Republic in 1931. Ten years later, the first three articles were reinstated by Generalissimo Francisco Franco's 1941 Convention with the Vatican. Eventually, a new concordat was signed in 1953.
The Concordat, the Roman Catholic religion was to continue, to the exclusion of every other, to be the only religion of the Spanish nation, and it was to be maintained, so far as his Catholic majesty has the power, "in all the rights and prerogatives which it should enjoy according to the law of God and canonical sanction."
The concordat changed the boundaries of dioceses, regulated the affairs of territories dependent on military orders, ecclesiastical jurisdiction, chapters, benefices. The right of presentation to certain of the latter was reserved to the pope; others were left to the queen.
Education in all the colleges, universities. etc. was mandated to conform to Catholic doctrine, and it was promised that the bishops, "whose duty it is to watch over the education of youth in regard to morals and faith," would meet no obstacle in the performance of that duty.
The bishops, and the clergy under them, were to enjoy the same rights in all else that regards their functions, especially in what concerns the sacred office of ordination. The government agreed to assure the respect due to them and lend its aid "notably in preventing the publication, introduction or circulation of immoral and harmful books."
Religious orders of men or women, who to contemplation add some work of charity or public utility, as education, care of the sick, missions, etc., were retained or re-established. The Spanish government agreed to pay the salaries of bishops, priests. In addition, it agreed to provide an income to churches and seminaries.