The Gutenberg Bible from Germany from 1455 AD, The Diamond Sutra from China from 868 AD, The Book of Kells from Ireland from 800 AD. All very old books, and all fairly well known to historians. But with the discovery in 2018 of what could be the earliest known siddur, a Jewish prayer book dated at around 840 AD – here is a list of 10 of the oldest known surviving books in the world today.