Schilling died a few months later, and was buried with honours at the Smolenskoye Lutheran Cemetery in Saint Petersburg. All records, models and equipment left by Schilling passed to Moritz von Jacobi, who would build the first operational telegraph line in Russia, connecting the Winter Palace with the Army Headquarters, in 1841. Works Cryptography Schilling's main contribution to cryptography was his bigram cipher, adopted for government use in 1823. The Schilling ciphers combined features of substitution ciphers and multiple-choice polyalphabetic ciphers using bigrams as source input. Each bigram consisted of two letters of source plaintext (in French language, the lingua franca of diplomacy), separated with a predetermined number of characters. The bigram was then converted to a number using permanent codetables containing 992 (32x31) pairs of alternative numbers. The method also involved padding source plaintext with random garbage and occasional encoding of single characters instead of bigrams. The first three sets of codetables prepared by Schilling were issued to viceroy of Poland Grand Duke Konstantin, special envoy to Persia prince Alexander Menshikov, and to foreign minister Karl Nesselrode on his journey to the United States. The method was used by Russian diplomats until the 1900s. Individual ciphers were rated safe for up to six years of service, later downrated to three years; in reality, some codetables remained in use for up to twenty years, violating all security protocols. Oriental expedition In the 1820s Schilling's scholarly papers on oriental languages brought him degrees and membership in British, French and Russian learned societies. He was a long-time friend to the chief of the Russian Orthodox mission in Peking, and leading Russian orientalist Nikita Bichurin (father Hyacinth). After Bichurin was disgracefully demoted and exiled, Schilling advocated for his pardon, and in 1826 he secured the transfer of Bichurin from imprisonment at Valaam Monastery to a desk job at the Foreign Ministry in Saint Petersburg. Schilling assisted Alexander von Humboldt during the initial stages of the 1829 expedition to Russia. After Humboldt had declined an offer to lead another expedition into the Russian Far East, the role was awarded to Schilling. Preparations began immediately after signing of the Treaty of Adrianople in September 1829. Core staff of the expedition included Schilling himself, Bichurin and Vladimir Solomirsky, bastard son of Dmitry Tatishchev. Alexander Pushkin, well acquainted to all three, wanted to join, but Nicholas I ordered him to stay in Russia. Schilling's main, covert mission