Tischendorf was a German Christian with a passion for the Bible. His goal was to locate and publish the oldest possible manuscripts of the Bible...to get us as close as possible to the words of the Bible writers, exactly as they wrote them. He was committed to this even if that meant departing from the Greek text that stood behind the translation of the Bible by Martin Luther, revered by Germans (i.e. the TR).
He spent years roaming about the libraries of Europe, looking for old manuscripts...and in 1843, his travels took him to the St. Catherine's Monastery in the middle of the Egyptian Sinai desert.
To stay safe from the temptations of the world, and possibly to stay safe from bandits, the monastery was built with no doors. So to get in, Tischendorf was hauled up the outside wall in a basket, by rope.
We are accustomed to thinking of monks as being godly scholars. Whether or not that is true in 21st century North America, it appears to have NOT been the case in 19th century Egypt.
Tischendorf discovered the monks were throwing ancient biblical manuscripts into a trash basket, and using them to start fires. He rescued 43 leaves from the Old Testament, and returned them to Europe. He came back years later and attempted to get possession of a manuscript of the entire Bible he had noticed on his first trip. But by this time, the monks had decided they had something valuable on their hands and didn't want to let it go.
At this point, the accounts begin to differ. According to Tischendorf, he negotiated a deal with the senior leaders of the monastery for the manuscript in return for 9,000 gold rubles from Russia (Tischendorf's expedition was by this time being financed by the Tsar of Russia).
According to the monks, he stole the manuscript, leaving behind a letter promising to return it in due time.
One way or the other, the may have been some intrigue afoot, as as portions of the manuscript were found to have been inserted into the bindings of other books to get them out of Egypt.
This manuscript, now called the Codex Siniaticus has proven to be the oldest manuscript in the world to contain the complete Greek Bible. It dates from A.D. 325, and has proven to be a key source that modern scholars use when trying to come up with the closest-possible-to-the-original text of the New Testament.
Upon his return to Europe, Tischendorf presented the manuscript to Tsar Alexander II, who then inducted Tischendorf into the Russian nobility (at which point his last name became von Tischendorf).
In 1933, Joseph Stalin (who had a lot of interest in cash, but not much interest in the Bible) sold Codex Siniaticus to the British Museum for £100,000. The codex has been digitized today and is available here.
This link will take you to II Cor. 4:16. Zoom in on the manuscript and it will give you practice in reading your Greek upper
case letters. Some centuries after this manuscript was made
If you find Siniaticus, with its absence of punctuation and spaces between words, difficult to read, it will give you a deep appreciation for all we owe to scholars like Westcott and Hort. They have learned to read upper case documents like Siniaticus, and have rewritten it in the lower case characters that we find so familiar.