Codex Sinaiticus is one of the oldest manuscripts of the Bible. It includes a complete New Testament as well as most of the Old Testament. By the style of the Greek manuscript, scholars date it to the Fourth Century (300-350 C.E.). The writing is in capital letters (“uncials”) without spaces between words in four columns per page (typical of the transition from rolls to books). Only Codex Vaticanus is likely to be as old or older. (A codex is a collection of leaves of paper or parchment bound in a book-form, as opposed to a rolled scroll.)
While modern Biblical scholarship looks to even older papyrus fragments as the ultimate ancient documents, the uncial codices are the basis for most modern English translations and variations from the King James Version.
In 1844, scholar/adventurer Lobegott Frederich Konstantin Tischendorf, a/k/a Constantin Von Tischendorf, located 43 pages of what we now call Codex Sinaiticus, at St. Catherine’s Monastery in the Sinai desert. Tischendorf claims to have noticed these 43 pages among papers stuck in a wastebasket to be burned to heat the library. The monks declined to give him the rest of the parchments.
In 1853 and in 1859 he returned to St. Catherine’s, this time with the active assitance of the Russian Government, and persuaded the monks to “lend” him the Codex, to copy it in Cairo. Eventually, through some political manuevering, he persuaded the abbot to give the complete manuscript to the Czar Alexander II, the Defender of their Orthodox faith. For his efforts on behalf of the Czar, he was given a title, hence we refer to him today as Constantin “von” Tischendorf. The manuscript was taken to St. Petersburg, where it remained until 1933. The manuscript was sold in 1933 by the Soviet Union to the British Museum for £100,000.
In 1975, monks at St. Catherine’s discovered additional pages of uncial manuscript from the Old Testament, believed to be part of the Codex Sinaiticus.
Tischendorf’s own account of how he found the mss.:
http://rosetta.reltech.org/TC/extras/tischendorf-sinaiticus.html
Facsimile of a page of John from Codex Sinaiticus:
http://www.earlham.edu/~seidti/iam/tc_codexs.html
On the difficulties of hand-copying uncial texts: http://www.cob-net.org/compare_uncials.htm