In addition to the now standard 27 books of the New Testament, Sinaiticus includes the Letter of Barnabas and most of the Shepherd of Hermas. The Old Testament given in the codex is a Greek translation called the Septuagint. This is the version of scripture quoted by Jesus and the apostles. Sinaiticus includes various works now classified as apocryphal, including 2 Esdras, Tobit, Judith, 1 and 4 Maccabees, Wisdom, and Sirach.
The codex was found in 1859 by German Bible scholar Tischendorf at the Monastery of St. Catherine at the foot of Mt. Sinai. Tischendorf claimed to have saved the codex as it was being fed to a fire by monks. Vellum does not burn easily, so this dramatic tale is unlikely. Tischendorf had an obvious motive to lie. He needed to justify taking the codex from the monastery.
Tischendorf published a print facsimile in 1862 and presented the manuscript to the Russian Ministry of Foreign Affairs, his sponsor. A photographic facsimile edition was published by Oxford University Press in 1911. In 1933, the Soviet government sold the manuscript to the British Museum. In 1975, the monks of St. Catherine discovered numerous parchment fragments. Among these fragments were twelve missing leaves from the Codex Sinaiticus.
There are 347 leaves of the codex in the British Library in London. Some 199 of these are from the Old Testament, while 148 of the New Testament. Forty-three Old Testament leaves are at the University of Leipzig in Germany, twelve at St. Catherine's Monastery, and six at the National Library of Russia. In July 2009, the Codex Sinaiticus Project used color digitized images of leaves kept at four institutions to united the codex online.