The Mudejars of Spain were Muslims living in Christian dominated areas, retaining some degree of religious freedom. In Castille, they had more freedom and autonomy than in Arragon.
They were however losing their language very fast, and hence most of them did not speak Arabic anymore, let alone read it.
There arose the need for the Mudejars to develop religious works in Castillian.
One such person from Segovia شقوبية was Ice de Gebir (الفقيه عيسى بن جابر الشاذلي الشقوبي), a Spanish Andalusian jurist, who wrote his works in Castillian. His name is spelled differently in different sources, for example: 'Isâ b. Jâbir is the closest to the Arabic that can be. Other spellings are Isa, Iça, Içe, Yça, Yza, and Ysa. His father's name can be spelled as Gebir, Jabir, or Yábir. The Gidelli seems to be a variation of ash-Shadhili.
Ice held the position of the "Grand Mufti of the Moors of Castille". In 1455 C.E., Ice travelled to Savoy in France, at the request of Juan de Segovia (John of Segovia) to translate the Quran to Castillian. From this Castillian translation, Juan translated it into Latin. Later, Juan used this translation for his book against the Quran ("De mittendo gladio in Saracenos").
Note that both Juan and Ice are from Segovia. Perhaps they knew each other from childhood, or were acquainted in some other way.
See: Censorship and Book Production in Spain during the age of the incunabula by Ignacio Tofiño-Quesada, and Henry C. Lea in A History of the Inquisition in Spain, Book 1, Chapter 2, footnote 98.
In 1462 C.E., Ice wrote a book in Castillian for his fellow Muslim Spaniards, titled "Breviario Sunni", "Breviario Segoviano" or "Suma de los principales Mandamientos y devedamientos de la Ley y Çunna". This was a book on religious duties, laws, and rituals.
Manuscripts of this book exist today in Spanish libraries, e.g. in the Biblioteca de la Real Academia de la Historia, in Madrid, and Biblioteca Nacional de Madrid (MS 2076).
See also, Four Texts for the study of the official voice of the Moriscos (machine translation from Spanish).
Recently, in the National Library of Mexico, a copy of the Breviario Sunni was found (machine translation) in books banned by the Inquisition of New Spain. The author of the article, M. Judith Feliciano Chaves, postulates that, like the above Mardid manuscript, it was in the possession of eclessiastical authorities who used it as a reference for identifying Muslim customs. Another possibility is that there were practicing Moriscos in Mexico soon after its settlement by Spaniards, and that this copy was confiscated during inquisitions. She comments that this is unlikely, since there are no 'referring marks, notes or names' in it.
The date of Ice's death is not known.
In Segovia today, there is a street by the name "Calle de Yza Gidelli", in memory of Ice de Gebir.