In his youth Gagarin was a Russian diplomat and served in Munich, London, and Paris. His wide circle of friends and contacts included Fedor Ivanovich Tiutchev, Mikhail Iurievich Lermontov, Petr Iakovlevich Chaadaev, Aleksandr Ivanovich Turgenev, Prince Petr Andreevich Viazemsky, Friedrich Wilhelm Joseph von Schelling, and Félicité de Lamennais. As a friend of Prince Petr Vladimirovich Dolgorukov, with whom he shared lodgings in St. Petersburg, he was suspected by some of complicity in Aleksandr Pushkin's fateful duel, though the scholarly consensus now is that he was guiltless in the affair. In 1842 Gagarin converted to Catholicism and subsequently took Holy Orders in the Society of Jesus. From the 1850s through the 1880s he lived, with some interruptions, in Paris, where he published polemical tracts on the history of the Russian Church and worked for a union between the Russian and the Roman churches in Catholicism. During this...