While there is no chance of holding a letter written by Paul’s own hand, what we have is an expansive volume of copies and versions. The Bible is the best-attested book of the ancient world. Neither Homer nor Plato have as much evidence pointing toward their integrity, in terms of sheer quantity. There are two main bodies of ancient documents that make up the textual evidence for the New Testament: Greek manuscripts (abbreviated MSS.) and Versions in different languages.
The Greek manuscripts have many identifying features which help one accurately date them. In particular, two classes of MSS. are the Uncials (older, and written in upper-case Greek letters) and Cursives (or running hand, employing lower-case Greek letters). Each of these classes brings benefits and limitations. The Uncials reflect an older perspective while the Cursives are more numerous and, therefore, provide more complete attestation. There are only 83 Uncials (several written as early as the fourth century or earlier) but nearly 2,000 cursives (the earliest written in the late tenth century). For comparison, there is only one uncial of each of the greatest works of Virgil, Ӕschylus, and Sophocles. Some MSS. have staggering antiquity, such as portions of the Bodmer Papyri (with a near-complete codex of the Gospel of John from around 200 AD) and the Chester Beatty collection of Biblical Papyri (with the Pauline epistles as early as 175 AD). One Uncial, though, has such immense value that it deserves brief mention:
Codex Sinaticus (designated א) – Discovered in 1859 by Tischendorf in St. Catharine’s Convent at the foot of the supposed Mt. Sinai. With some difficulty, it was obtained from the convent, all 790 pages worth. What makes it so important is its antiquity combined with its completeness. It contains every New Testament book and much of the Old Testament. By nearly every Bible critic, both secular and religious in perspective, it is a work of scriptural literature with inestimable value. Most modern New Testaments are based, at least in part, on this MSS. Along with Codex Alexandrinus it is one of the most important discoveries ever in Biblical scholarship, and is the hallmark of the Alexandrian text-type MSS.
Next, we have Ancient Versions, which are translations of the New Testament into languages other than Greek. Their value comes from the fact that many of them are older and in better condition than their Greek cousins. The Peshito Syriac, for example, is likely a translation of a Greek MSS. from the second century. It is still in limited use today amongst Syrian Christians. Before the third century, the Old Latin Version was made in Northern Africa (where Latin was the predominant language). Early Christians had great evangelistic success in Carthage and other regions, precipitating the need for a Latin Bible to be produced. The most famous of these versions, though, is the Latin Vulgate (from the Latin word for common). Its primary translator, Jerome, utilized what he termed “ancient Greek manuscripts”, as well as current Latin versions, in preparing this massive work from 382-385 AD.
Found in libraries, closets, and caves in dry, warm climates, scraps and scrolls dating to within a few generations of their original authors have been found all over the ancient world. Depositories of ancient documents exist in Europe, Africa, and Asia. With so much information at hand, the science of Biblical criticism has an embarrassment of riches.