Gagarin was of the princely Russian family which traces its origin to the ancient rulers of Starodub; born at Moscow, 1 August, 1814; died at Paris, 19 July, 1882.

Ivan (Johannes) was the son of the Russian state-councillor, Prince Sergius Gagarin, and Barbara Pushkin. He entered the service of the state at an early age, and was first named attaché to his uncle, Prince Gregory Gagarin, at Munich, on whose death, in 1837, he acted as secretary to the legation at Vienna. He was afterwards transferred to the Russian embassy at Paris, where his services were requisitioned in a similar capacity. He frequented the salon of his near relation, Madame Sophie Swetchine, and was on terms of familiar intercourse with Ravignan, Lacordaire's successor in the pulpit of Notre-Dame. Probably this dual influence assisted in bringing about his conversion to Catholicism, in 1842. On 19 April of that year Gagarin made his profession of faith, and was received into the Church by Ravignan, thereby, according to Russian law, putting an end to his diplomatic career, and forfeiting all rights to his inheritance. In the latter half of 1843 he entered the Society of Jesus, and passed his novitiate at Saint-Acheul. He was afterwards employed in professorial work at Brugelettes, where he taught church history and philosophy, at the College of Vaugirard and the school of Ste-Geneviève, and at Laval. He spent some time in Versailles and, in 1855, was back at Paris, from which date onward his pen was ever actively employed in the interests of religion and learning. Gagarin's literary output was considerable; many of his articles which appeared in current reviews and periodicals were afterwards collected and published in book form.

As a polemist Gagarin was thorough, and his work as a religious propagandist was of great importance. His grand object was to extinguish dissension and schism amongst the Slavonic peoples and win over Russia to the Church Universal. In conjunction with Fr. Daniel, Gagarin founded (1856) the journal "Etudes de théologie, de philosophie et d'histoire" (merged into "Etudes religieuses, historiques et littéraires", 1862); he re-established the "Œuvre de Prop. des Sts. Cyrille et Méthode" (1858), to promote corporate union amongst the Churches; and contributed to the "Contemporain", "Univers", "Ami de la Religion", "Précis historiques", "Correspondant", "Revue des questions historiques", etc. The "Polybiblion" (Paris, 1882), another review in which articles appeared from the pen of Gagarin, exhibits (XXXV, 166-188) a long list of his writings. These include: "La question religieuse dans l'Orient" (1854); "La Russie sera-t-elle catholique?" (Paris, 1856), tr. German (Münster, 1857), and rendered into other languages; "De l'Enseignement de la théologie dans l'Eglise russe" (1856); "Un document inédit sur l'expulsion des Jésuites de Moscou" (1857); "Les Starovères, l'Eglise russe et le Pape" (1857); "De la Réunion de l'Eglise orientale avec l'Eglise romaine" (1860); "Réponse d'un Russe à un Russe" (1860); "Tendences catholiques dans la société russe" (1860); "L'avenir de l'Eglise grecque unie" (1862); "La primauté de Saint-Pierre et les livres liturgiques de l'Eglise russe" (1863). Gagarin also spent several years in Constantinople, where he founded the Society of St. Dionysius the Areopagite, which aims at reuniting the Greek and Latin Churches. With this object, too, he published "L'Eglise roumaine", etc. (1865); "Constitution et situation présente de toutes les Eglises de l'Orient" (Paris, 1865); "Les Eglises orientales unies" (1867), scholarly and comprehensive studies on the Oriental Churches. Amongst works of Gagarin's more mature years are: "Les hymnes de l'Eglise russe" (1868); and the very interesting and discursive "Le Clergé Russe" (new ed. Brussels, 1871; tr. London, 1872). The latter is a collection, in book form, of a series of articles published in the "Etudes religieuses" under the title "La réforme du clergé russe", an indictment of the encroachments of civil aggression on ecclesiastical right. The "Mémoires d'Archetti" [Paris, Brussels, 1872 - "Les Jésuites de Russie" (1783-1785)]; and "Religion et Mœurs des Russes", edited by Gagarin (Paris, 1879), are further proofs of his great activity. Almost all the above were published at Paris. A portion of his works were re-issued by Brühl, in "Russische Studien zur Theologie und Geschichte" (Münster, 1857); and by Huttler, in "Katholike Studien" (Augsburg, 1865). When the religious orders were expelled from France, Gagarin went to Switzerland, but soon returned to Paris, where he died.

STREBER in Kirchenlex., s. v.; VAPEREAU, Dict, des Contemp., 6th ed. (Paris, 1893), s. v. Gagarine; ROSENTRAL, Convertitenbilder, III, ii, 194, sqq. See also, for indication as to sources, author's preface to various works.

P. J. MacAuley.