Codex Sinaiticus is a priceless treasure. Copied around the middle of the fourth century, in the south-eastern Mediterranean, it is the earliest extant manuscript to contain the complete New Testament and the oldest and best witness for some of the books of the ancient Greek version of the Old Testament, the Septuagint. The manuscript originally contained the entire Bible, both Old and New Testaments, in one huge volume. Its name derives from the monastery of St Catherine at the foot of Mount Sinai where it had been preserved until the middle of the 19th century.

Codex Sinaiticus was copied by a team of at least three scribes writing simultaneously in a script using capital or upper case letters known as majuscule. The manuscript is famous not only for some of its unusual textual variants (such as the missing account of the resurrection at the end of St Mark’s Gospel) but also for the extensive number of corrections to its text.

Sinaiticus is critical to our understanding of the history of the Christian Bible. It is one of the three earliest surviving manuscripts into which the full collection of books (the ‘canon’) found in the Christian Bible was copied, although with some differences from today’s printed Bibles. It contains some additional books which many Protestant Christian denominations place among the Apocrypha of the Old Testament (such as Maccabees and the Wisdom of Sirach), as well as the Epistle of Barnabas (a letter written by an unknown author claiming to be the apostle Barnabas) and a collection of visionary texts known as the Shepherd of Hermas at the end of the New Testament.

The manuscript also marks a pivotal point in the history of the book: it is one of the earliest large bound books (‘codex’) to have survived from late Antiquity. Containing the entire Christian Bible in one volume, it reflects a major technical innovation, as bound books with parchment pages began to take over from the earlier formats of papyrus rolls and booklets. The significance of the development of the bound book can be compared to the introduction of printing or computers.

Today, parts of the manuscript are held in four institutions: Leipzig University Library in Germany, the National Library of Russia in St Petersburg, St Catherine’s Monastery in Sinai, and the British Library, where the largest part of the manuscript (347 folios) is now preserved. As a result of an international collaborative project between these four institutions, images of all the surviving parts of Codex Sinaiticus were reunited virtually in 2009 on an interpretative website ( The text of Codex Sinaiticus in these images was linked word-by-word to a new online transcription of the whole manuscript. The four partners in the project also agreed an account of the history of the manuscript which was published on the website (