The Torah is the oldest part of the Bible, written in ancient Hebrew and comprising three sections: the Pentateuch, which is sometimes referred to as “The Law” and includes the first five books of the Bible; The Prophets, which includes all the major and minor prophetic writings; and The Writings, which includes Psalms, Proverbs, and a number of other books. The original documents that comprise the Torah—sometimes called the “autographs”—are not in the possession of any organization. The date of beginning writing of the Torah is likely somewhere between 1450 BC and 1400 BC. The last part of the Hebrew scriptures was written about 400 years before Jesus was born.
The Christian Greek scriptures started to be written some years after Jesus’ death and resurrection, and the last of its little books was completed by AD 95 at the latest, but perhaps before AD 70 (as no part of the New Testament mentions the destruction of Jerusalem and its temple in AD 70.) There are no autographs of them.
As for the complete Bible, containing both the Hebrew and the Greek scriptures, two known proto-Bibles still exist. They are dated to about 350 A.D. One is the Codex Amiantinus in the Biblioteca Medicea Laurenziana, in Firenze [Italy]. The first Latin Vulgate Bible was apparently published about 405 A.D. which might be the first translation of the entire Bible. (The Hebrew scriptures had been translated into Greek shortly before Jesus was born and this is known as the Septuagint version, the LXX.)
For the New Testament, there are 5,664 Greek manuscripts (some dating as early as 125 AD) and a complete New Testament that dates from 350 AD.
It is not paganism that has corrupted the initial or later manuscripts of the Bible. It is interpretations placed on them by people who believed some pagan ideas that was the problem. But the text of the Bible itself has never been corrupted by paganism as it constantly, uniformly, and consistently condemns paganism.