The first five books of the Bible are attributed to Moses and are commonly called the Pentateuch (literally “five scrolls”). Moses lived between 1500 and 1300 BC, though he recounts events in the first eleven chapters of the Bible that occurred long before his time (such as the creation and the flood).
All this leads to the conclusion that the earliest writings in the Bible were set down around 1400 BC. The writings of the thirty or so other contributors to the Old Testament span a thousand years. They recount the times and messages from Moses’ successor, Joshua, to the last of the Old Testament prophets, Malachi, who wrote his little tract around 450 BC.
Then there is a 500-year period when no writings were contributed to the Bible. This is the period between the testaments, when Alexander the Great conquered much of the world and when the Greek language was introduced to the Hebrews. Indeed, they began to use Greek so much that the Hebrew language was replaced by Greek and by another language, Aramaic, which was spoken all over that area of the world at that time.
The New Testament was written during a much shorter period, i.e. during the last half of the first century AD.