The collection is composed of works from the personal libraries of Sultan Zaydan Bin Ahmed and his father Sultan Ahmed al-Mansur, his brother Sheikh al-Ma'mun, and Abu Faris. The library contained treatises in different fields and in a number of different languages, among them Turkish, Farsi, and Latin. Moroccan diplomats had been asking for them from the beginning of the 17th century to 2009, when Spain allowed Morocco to make microfilm scans of the documents, which King Juan Carlos I of Spain delivered to Morocco on July 16, 2013 during an official visit.https://royalcorrespondent.com/2013/07/17/his-majesty-king-juan-carlos-i-of-spain-visits-rabat-morocco-videos/