In May 1844 and February 1859, Constantin von Tischendorf visited the monastery for research and discovered the Codex Sinaiticus, dating from the 4th Century, at the time the oldest almost completely preserved manuscript of the Bible. The finding from 1859 left the monastery for Russia, in circumstances that had been long disputed. But in 2003 Russian scholars discovered the donation act for the manuscript signed by the Council of Cairo Metochion and Archbishop Callistratus on 13 November 1869. The monastery received 9000 rubles as a gift from Tsar Alexander II of Russia. The Codex was sold by Stalin in 1933 to the British Museum and is now in the British Library, London, where it is on public display. Prior to September 1, 2009, a previously unseen fragment of Codex Sinaiticus was discovered in the monastery's library, as well as among the New Finds of 1975. On other visits (1855, 1859) Constantin von Tischendorf also amassed there more valuable manuscripts (Greek, Christian Palestinian Aramaic, Georgian, Syriac) and took them with him to St Petersburg and Leipzig, where they are stored today.