Valeriano was born in
Milan on 11 October 1586. His father, Costantino Magni came from an ancient and noble Italian family. At the age of two, Magni was taken by his parents from Italy to Prague. As a young man, Magni entered the Capuchin Order in
Prague. He spent his first years as
lector, and soon gained a great reputation as a
preacher. In 1624 he was appointed Franciscan provincial of
Bohemia and two years later he was named Prefect and
Apostolic Vicar of the church's mission to
Poland, Bohemia,
Hungary, and
Germany. He collaborated with various papal diplomats, particularly with the apostolic nuncios
Pier Luigi Carafa in
Cologne,
Giovanni Battista Maria Pallotta,
Ciriaco Rocci and
Malatesta Baglioni in the
Archduchy of Austria; Onorato Visconti, Mario Filonardi and Giovanni de Torres in the
Polish–Lithuanian Commonwealth. His activity is documented by a large collection of letters preserved in various European archives. Magni was greatly respected by
Holy Roman Emperors
Ferdinand II and
Ferdinand III, as well as by King
Władysław IV Vasa, who employed him on several diplomatic missions. In July 1647 he performed a vacuum experiment (so-called
Torricelli's experiment) before a distinguished audience at the
Royal Castle in
Warsaw. The publication of the experiment aroused great controversy in 1640s. The conversion of the
Calvinist theologian
Bartholomaeus Nigrinus, who was appointed confidential secretary to Władysław IV, was certainly a result of his influence, and it strengthened the Catholic party in
Poland. Władysław IV solicited a cardinal's hat for Magni, but the opposition of the Jesuits prevented his elevation to the cardinalate. Magni was very close to the Archbishop of Prague,
Ernst Adalbert von Harrach.
Landgrave Ernst of Hesse, who had been converted at Vienna on 6 January 1652, and who knew Father Valeriano, summoned Capuchins to
St. Goar on the Rhine, and was present at the religious disputation between Valeriano and Peter Haberkorn of
Giessen held at
Burg Rheinfels in 1651. Magni had a long-standing feud with the
Jesuits, against whom he harbored a strong aversion. It was by his advice that
pope Urban VIII abolished the
Jesuitesses in 1631. On the appearance of his
pamphlet Contra imposturas Jesuitarum in 1659, he was summoned to appear before the papal court. As he did not obey the summons he was arrested in Vienna at the instance of the
nuncio, but Ferdinand III's intervention secured his release. He then moved to
Salzburg, where he remained for the rest of his life. He died on 29 July 1661, aged 73. ==Selected works==