On September 16th 1859, the eminent German Biblical Theologist K. Tischendorf, under the auspices of the Russian ambassador to the High Porte, prince A. Lobanov (Egypt was part of the Ottoman Empire at the time), received the main body of the Codex Sinaiticus of the Holy Bible on loan from Sinai Monastery, in order to take it to Russia, where it would be published, and accordingly signed the relevant affidavit. The ambassador himself had already vouched for the loan terms in a personal Letter of Guarantee to the
Monastery on 10/09/1859; these terms were accepted by the Holy Synaxis of the Fathers of the Sinai Brotherhood in an official act on 16/09/1859 [see. pp.58-59]. The publication would be dedicated to Tsar Alexander II and the manuscript was to be returned to the monastery, which explicitly was to remain its rightful owner during the whole process.

Since the Codex remained in St. Petersburg after its publication in 1862, the new Russian ambassador to Constantinople N. Ignatiev was asked to handle the case from now on; he duly pressured the Ottoman Auhorities to refuse to recognize the new Archbishop of Sinai Callistratus, and also withheld all monastery revenues from Russia, demanding that it must officially donate the Codex to the Tsar. The confidential, unofficial correspondence between the two sides reveals the struggle of the monastery Brotherhood to avoid submitting to this diplomatic coercion, despite the ensuing, three-year-long financial and administrative impoverishment of the monastery. A sort of compromise was prescribed after the intervention of Ignatiev himself in Egypt in 1869. Hence, the Codex remained in Russia, and in 1933 was sold by the Soviet Government to the British Museum.