Full Decipherment of Pedro de Ayala's Letter to Ferdinand and Isabella (1498)

Three historians have achieved complete transcription and decipherment (as well as full translation into English) of a partially enciphered letter from Pedro de Ayala to Ferdinand and Isabella dated 25 July 1498. (I thank George Lasry for bringing a report in French by Korben to my attention. Its source is Medievalists.net in English.)
The paper was published on 16 March 2026:
Adrian William Jaime, Valeria Tapia Cruz, Mairi Cowan (2026), "Tudor England and Stewart Scotland Through Spanish Eyes: A Complete Transcription and Translation of Pedro de Ayala's Letter of 1498 to King Ferdinand of Castile and Queen Isabella of Aragon", DOI: https://doi.org/10.1111/rest.70019 (an online version before inclusion in an issue of Journal of the Society for Renaissance Studies).
The original letter in the archives (PTR,LEG,52,166 f.857) is available at PARES.

The letter itself has been known to historians by a calendar by Bergenroth (Google, p.168) and also by Almazán's summary "currently archived together with the original manuscript". (Quotations are from the paper. See several paragraphs from n.74.)
Bergenroth deciphered passages in cipher and his key is in PRO31/11/11 in three versions ("Correspondence with Pedro de Ayala and Don Martin", "Cifra de Don Pedro de Ayala", "1498 Pedro de Ayala"; see "Bergenroth's Papers on Spanish Ciphers in PRO 31/11/11"). However, it has been pointed out that "his edition contains mistakes, and much of the English version printed in the Calendar of State Papers is more a paraphrase than a direct translation" and there have been works for a more accurate edition for parts of the letter. The authors' key "builds off the work of Luis A. Robles Macías ["Transcripción revisada del informe de Pedro de Ayala de 1498"], adding new symbols based upon how Almazán deciphers the letter in his summary."