One of the oldest surviving manuscripts of the Liber Juratus, dating from the end of the 14th or the beginning of the 15th century, is manuscript No. 313 from the collection of Hans Sloane in the British Museum. It was partly owned by the mathematician and magical experimenter John Dee, in whose Mysteriorum Libri Quinti, or Five books of mystical exercises (1581–1583), the Sigillum Dei played a central role and gained the suffix Sigillum Dei: Emeth or Aemeth ("Truth").[5]