Codex Regius codex was compiled by scholars who looked at many different ancient codices, which included the Old Babylonian codex, the Hebrew codex and the Greek codex.
Its authors have said it is the oldest codex in the world and they think the texts in it were actually written in the 2nd century BC.
But this is disputed, as the Greek and Hebrew texts show no signs of being copied from one another.
The codex has been published for decades by various Greek and Roman scholars, but only a handful of scholars have seen it.
This week, we’ll be looking at the best codexs for the next 50 years.