The bible is from the early 4th century and written in Greek on parchment leaves. By putting it online it is available for study by scholars around the world creates opportunities for collaborative research that would not have been possible just a few years ago.
The Codex Sinaiticus was found in 1844 after lying undisturbed in a Sinai monastery. It was then split between Egypt, Russia, Germany and Britain.
Dr Scot McKendrick, head of Western manuscripts at the British Library, said:
This 1,600-year-old manuscript offers a window into the development of early Christianity and first-hand evidence of how the text of the Bible was transmitted from generation to generation.
This link on differences to what we know now may interest.