The Babylonian Talmud was composed by the late 5th or early 6th centuries, no later than 541-542 CE when the Black Plague, the so-called Plague of Justinian, appeared in Byzantium. It was the culmination of about three centuries of scholarship.
The Babylonian Talmud comprises more than 1.8 million words. One way to put the size of the document in perspective is to compare it with the other major and legal compilation of the period, the Codex Justinianus, or Digest of the Roman emperor Justinian I, which contains roughly 800,000 words.
"Far beyond any other legal compilation of Late Antiquity, the Babylonian Talmud is marked by a salient characteristic, its continuous and unending dialogue. The debates are not haphazard. Certain authorities who were contemporaries or near-contemporaries debate all sorts of issues related to the Mishnah, issues that are sometimes only remotely relevant to them personally.
"Some statistics will give us an idea of what is happening. The Babylonian Talmud is the creation of at least seven generations of Babylonian authorities, and contains several generations of Israeli authorities as well. However, of the hundreds of authorities mentioned by name, more than forty thousand times in toto, only a dozen or so dominate the discussion and are scattered in pairs. Chronologically, Rav and Samuel, R. Óuna and R. Óisda, R. Naòman and R. Sheshet or R. Yehuda, Abaye and Rava, R. Papa and R. Óuna b. R. Joshua, and R. Ashi overwhelmingly carry forward the debate.
"These debates are often arranged as structured discussions on a given topic, so that they appear to be stenographic records of actual debates. This appearance is literary only, however, as few of these authorities lived in close proximity" (Yaakov Ulman, "The Babylonian Talmud in its Historical Context", Printing the Talmud: From Bomberg to Schottenstein, 20-21, http://www.printingthetalmud.org/essays/2.html, accessed 12-05-2208).