The Llibre de Menescalia is a 1436 Catalan manuscript by Manuel Dieç, translated into Spanish as Libro de Albeytería,[1] that became the reference veterinary work about horses of the 15th and 16th centuries. At the time, the Catalan language had spread throughout the Mediterranean and was understood in a broad part of Europe for its similarity to Occitan and other languages. The book also had great success in Castile, for it was translated into Spanish in 1499 and republished in that language several times. The work consists of two books. The first, Book of Menescalia, deals with the external anatomy of the horse, qualities that must concur for the choice of the parents, coat, the way to raise the foal, etc. The second, Treatise of the Menescalia of the mules, is about the mules widely used in Catalonia.[2]