Theologian and papal envoy, b. at Mantua in 1533 or 1534; d. at Ferrara, 26 Feb., 1611. At sixteen he went to Rome to study, familiarized himself with many languages, and became secretary to Cardinal Ercole Gonzaga. In 1559 he entered the Society of Jesus, and in 1560 was sent to preach against heresy in Savoy. Passing on to France he was ordained priest in 1561, and preached at Paris, Bayonne, Rouen, and elsewhere, converting many Calvinists. He became rector of the colleges of Avignon and Lyons, and in 1573 was secretary to the General of the Society, Everardo Mercuriano. Gregory XIII himself was among those who learned to appreciate his merit while he occupied the last-named position. When John III of Sweden expressed his desire to become a Catholic, the pope, in 1577, made Possevinus his special legate to that court, and Possevinus also had to negotiate with the courts of Bavaria and Bohemia to secure support for John in the event of political complications. The Jesuit envoy, attired as a secular, was received with great honour in Sweden, and the king made his profession of the Catholic Faith.

Many difficulties arose when measures for the conversion of Sweden were debated. Possevinus returned to Rome with proposals, some of which were judged inadmissible. Through his constant efforts several colleges (the German College at Rome, those of Braunsberg, Fulda, Olmütz, Prague, and others) received Swedish youth, with the object of forming a national Catholic clergy. At the close of 1578 he returned to Sweden as nuncio and Vicar Apostolic of Scandinavia. On his way, he again visited the Duke of Bavaria, the King of Poland, and the emperor. Disconcerted by the refusal of Rome to accept the king's terms, and thwarted by sectarians, who had the advantage in numbers and influence, Possevinus could do nothing but comfort and encourage the few Catholics remaining in Sweden. He displayed the greatest devotion on the occasion of an epidemic, when the sick were left helpless by the Protestant ministers.

In 1580 he turned in Rome. In the meantime the Tsar Ivan IV sought the pope's mediation with Stephen Báthori, King of Poland, in the cause of peace. Possevinus was sent as papal legate (1581) to negotiate the re-union of the Russian Church with Rome. The negotiations made with the Russian envoys in Poland proved nugatory, as the King of Poland insisted on profiting by his successes in war, and Possevinus went to Russia to treat with the Tsar. He wisely laid down as preliminary conditions of peace with Poland the liberty of Catholic worship for foreigners in Russia and free passage for pontifical legates. These were granted pro forma. His overtures of reconciliation with Rome were met only with reassuring words. In 1582 the Tsar signed a treaty of peace, compelled by Polish victories. Possevinus left Moscow laden with honours but not deceived as to the success of his efforts: Ivan the Terrible had negotiated with the pope only to mislead both Rome and Poland. Having returned to Rome, Possevinus was immediately sent back to Poland as nuncio, to induce the king to combat heresy in Livonia and Transylvania. He himself visited these countries, preaching and arguing with the heretics.

At the Diet of Warsaw, in 1583, he obtained the passage of resolutions favourable to Catholicism. His efforts were ineffectual in the treaties between Poland and the emperor, on which business he went twice to the Court of Rudolph II. He still stayed in the North, preaching in Livonia, Saxony, Bohemia and Transylvania, writing treatises against the innovators and distributing books on Catholic doctrine. He did much towards the reconciliation of the Ruthenians, and had a large share in the founding of the college of the Jesuits at Vilna. He also wrote treatises against the adversaries of the re-union. Through his exertions the Collegium Hosianum of Braunsberg was enlarged for the reception of Swedes and Ruthenians; at Olmütz and Claudiopolis, in Transylvania, colleges were established for similar purposes. In 1587 he was invited to teach theology at Padua, where he remained for four years. Among his disciples there was St. Francis of Sales. Returning to Rome, he devoted his time to theological, historical, and philosophical studies. Having played an important role in the recognition of Henry IV of France, he was expelled from Rome by the Spanish party. He then made extended tours to visit the libraries of Italy in quest of books, as on former occasions, in which task he was generously aided by Paul V.

Antonio Possevinus represented the literary, scientific, and diplomatic type of Jesuit, performing important political missions, establishing schools of science and letters, and applying himself to diplomatic protocols and classical authors with equal assiduity. Had he not met with insurmountable difficulties in Sweden and Russia, and in negotiating the treaties between Poland and the empire, he would have left a still deeper trace on the political history of the Church and of Europe. His writings include "Moscovia" (Vilna, 1586), an important authority on Russian history; "Dell sacrificia della Messa" followed by an appendix, "Riposta a P. Vireto" (Lyons, 1563); "Il soldato cristiano" (Rome, 1569); "Notæ verbi Dei et Apostolicæ Ecclesiæ" (Posen, 1586). His most celebrated works are the "Apparatus sacer ad Scripturum veteris et Novi Test." (Venice, 1603-06), where he records and analyses more than 8,000 books dealing with sacred Scripture; and the "Bibliotheca Selecta" (Rome, 1593), treating of the method of study, teaching, and practical use of various sciences; the second part contains a critical bibliography of various sciences. (Several chapters of this book have been published separately.) Parts of his letters were published by A. M. Gratianus Borgo in "De scriptis ab Ant. Possevino ad Aloysnium fratrem litteris" (Florence, 1645-46).

THEINER, Schweden u. s. Stellung zum hl. Stuhl (Augsburg, 1838); PIERLING, Possevini missio moscovitica (Paris, 1882); Idem, Un nonce du pape in Moscovie (Paris, 1886); Idem, Bathory et Possevin (Paris, 1887); La Russie et le S. Siège (Paris, 1897); BLAUDET, La Suède et la S. Siège (Paris, 1907). See also biographies of Possevinus by d'ORBIGNY (Paris, 1712); GHEZZI (Rome, 1759); KARTTUNEN (Rome, 1908); SOMMERVOGEL, Bibliothèque des éscrivains de la C. de J. VI, 1061-93; IX, 781. - For the relations of Possevinus with Báthori and Tsar Ivan, see histories of Poland.

U. BENIGNI