Voynich Manuscript (c. 1400 A.D.) -For years, people thought it was a hoax. The Voynich Manuscript seems like it could be a prop in a King Arthur tale, but there’s no author to tell us what it means. One of the great linguistic mysteries in history, the Manuscript is written in “Voynichese” — an unknown language. Carbon-dated to fifteenth-century Europe, it appears to be the only remaining artifact of its culture. Many scholars have spent their careers trying to crack its code, to no avail.