Martin John Spalding, an American prelate, born in Marion co., Ky., May 23, 1810, died in Baltimore, Feb. 7, 1872. He graduated at St. Mary's college, Lebanon, in 1820, studied theology, and went to Rome in 1830 to complete his course at the college of the propaganda. He was ordained priest on Aug. 13, 1834, returned to Kentucky, and was appointed pastor of the cathedral of Bardstown. In February, 1835, he founded the "Catholic Advocate," with which he was connected till 1858. He also founded the "Louisville Guardian" in 1854. In 1838 he was elected president of St. Joseph's theological seminary, Bardstown; in 1840 became pastor of St. Peter's church, Lexington, and in 1841 again pastor of the cathedral at Bardstown. He was invited to deliver a series of discourses on the Roman Catholic church in the cathedral of Nashville in 1843; and he afterward lectured in the chief cities of the United States and Canada. His yearly lectures from 1844 to 1847 were published with the title of "Evidences of Catholicity" (1847; 4th ed., Baltimore, 1866). He was appointed coadjutor bishop of Louisville, Aug. 10, 1848, with the title of bishop of Lengone in partibus infidelium, and was consecrated on Sept. 10. He established a colony of Trappist monks at Gethsemane near Bardstown, and a house of Magdalens in connection with the convent of the Good Shepherd. In 1850 he became bishop of Louisville as successor of Dr. Flaget, whose life he wrote (Louisville, 1852), and built a magnificent cathedral.

In May, 1852, he was present at the first plenary council of Baltimore, obtained the erection of the new see of Covington, and urged the establishment of a system of parochial schools in every diocese. He went to Europe in November, 1852, obtained in Belgium Xaverian brothers for the parochial schools of Louisville, and from Archbishop Zurysen of Utrecht several priests and a colony of sisters to instruct the deaf and dumb. Having taken steps for the foundation of an American college at Louvain, he returned to the United States in April, 1853, and was involved in a controversy with George D. Prentice of the Louisville "Journal" at the beginning of the Know-Nothing movement in 1855. He published his "Miscellania" during this agitation. In the three provincial councils of Cincinnati, in 1855, 1858, and 1861, Bishop Spalding bore a leading part, and drew up the collective address of the bishops at their close. Another controversy with George D. Prentice grew out of a review by Bishop Spalding of Joseph Kay's work on common school education in Europe, the bishop advocating a denominational system of common schools, such as exists in most European states.

In his own diocese he introduced a system of church government calculated to secure the rights of the inferior clergy, and preserve them from arbitrary rule. In 1860 he published "A History of the Protestant Reformation in Germany and Switzerland" (2 vols. 8vo, Louisville; 4th ed., Baltimore, 1800), enlarged from a review of D'Aubigne first published in 1844, and delivered a course of lectures at the Smithsonian institution on the history and elements of modern civilization. He succeeded Dr. Kenrick as archbishop of Baltimore, May 12, 1804, and took possession of his see on July 31. One of his first cares was to found an industrial school for boys intrusted to the Xaverian brothers, which was opened Sept. 8,1866. As apostolic delegate, he convened the second national council of Baltimore, Oct. 7, 1866, and had the principal part in preparing the measures submitted to its deliberations, and in drawing up the acts of the council in so complete a form as to make the work a standard manual of American canon law (Concilii Ple-narii Baltimorensis II. Acta et Decreta, Baltimore, 1808). To him is mainly due the foundation of the " Catholic Publication Society " of New York, and of the monthly periodical called the " Catholic World." He took a conspicuous part in the council of the Vatican (1869-70). Together with other bishops of the United States, he wished for an immediate and final doctrinal judgment on the question of pontifical infallibility, but preferred an indirect and implied definition, consisting in the formal condemnation of every sentiment opposed to the inerrancy of the supreme teaching office of the pope.

On Archbishop Spalding's arrival in Rome a postulatum in this sense was drawn up by him and signed by the American bishops. Subsequently some of the leading reasons on which the, postulatum was grounded were publicly quoted by Bishop Du-panloup as arguments against the opportuneness of a doctrinal definition. Passages from the late Archbishop Kenrick's theology were also alleged in support of the opposition. This was resisted by Archbishop Spalding in a letter to Bishop Dupanloup (April 4, 1870), in which he vindicated the orthodoxy of his predecessor, and explained the opinions of the American bishops. At the opening of the council he had been appointed a member of the commission of 16 on postulata and the decided stand taken by the majority of the council in favor of an immediate and formal definition finally induced him and his co-signers to make no further opposition. Archbishop Spalding edited with an introduction and notes Abbe Darras's " General History of the Catholic Church" (4 vols., New York, 1866).