Codex Escalada (or Codex 1548) is a sheet of parchment signed with a date of "1548", on which there have been drawn, in ink and in the European style, images (with supporting Nahuatl text) depicting the Marian apparition of Our Lady of Guadalupe to Juan Diego which allegedly occurred on four separate occasions in December 1531 on the hill of Tepeyac north of central Mexico City. If authentic, and if correctly dated to the mid-16th century (as tests so far conducted indicate), the document fills a gap in the documentary record as to the antiquity of the tradition regarding those apparitions and of the image of the Virgin associated with the fourth apparition which is venerated at the Basilica of Guadalupe. The parchment first came to light in 1995, and in 2002 was named in honour of Fr. Xavier Escalada S.J. who brought it to public attention and who published it in 1997.