Postscript to Mary's letter to Babington — Walsingham's "Decypherer" forged this cipher postscript to Mary's letter to Babington. It asks Babington to use the—broken—cipher to tell her the names of the conspirators.
Alongside Babington's record of the cipher used.
Photo Credit: By Thomas Phelippes and Anthony Babington - Public Domain, https://commons.wikimedia.org/w/index.php?curid=680810