“Perhaps we can appreciate how wealthy the New Testament is in manuscript attestation if we compare the textual material for other ancient historical works. For Caesar’s Gallic Wars (composed between 58 and 50 B.C.) there are several extant MSS, but only nine or ten are good, and the oldest is some 900 years later than Caesar’s day. Of the 142 books of the Roman history of Livy (59 B.C.-A.D.17), only 35 survive; these are known to us from not more than 20 MSS of any consequence, only one of which, and that containing fragments of Books III-VI, is as old as the fourth century. Of the 14 books of the Histories of Tacitus (c. A.D. 100) only four and a half survive; of the 16 books of his Annals, 10 survive in full and two in part. The text of these extant portions of his two great historical works depends entirely on two MSS, one of the ninth century and one of the eleventh.
The extant MSS of his minor works (Dialogus de Oratoribus, Agricola, Germania) all descend from a codex of the tenth century. The History of Thucydides (c. 460-400B.C.) is known to us from eight MSS, the earliest belonging to C. A.D. 900, and a few papyrus scraps, belonging to about the beginning of the Christian era. The same is true of the History of Herodotus (B.C. 488-428). Yet no classical scholar would listen to an argument that the authenticity of Herodotus or Thucydides is in doubt because the earliest MSS of their works which are of any use to us are over 1,300 years later than the originals.” -F.F. Bruce, The New Testament Documents