It is the work of priests appointed by the Emperors of the Roman Empire who were ordered to create a hierarchical centralised state religion in order to control the politics and religions of the Roman Empire.
The books that make up the Bible are much older than that.
The real conspiracy is more to the point of how (and why) it was decided to leave some books out, include others, etc. The Bible isn't the whole story, but rather selected pieces of the whole puzzle, reassembled to form a completely different overall picture, and one designed to suit the organizers' purposes...(namely control).
