The real identity of the author writing On the Nature, Kinds, and Deeds of the Horse, a manuscript that has languished in a Moroccan library for centuries, has puzzled many researchers. The name given in the manuscript, of which only three copies are known to exist, is Andrad of Seville. For years it has been assumed that Andrad of Seville might have been Imam Faqih Hakim Abu al-Qasim Mohammed bin Mohammed al-Ummawi, known as Ibn Andras from Mercia, who died in AH 674. Yet, it can be gleaned from the introduction within the manuscript that its author wrote it in a language other than Arabic, and that the text is in fact an Arabic translation. This paper shall demonstrate that the manuscript's author is not, as previously believed, Ibn Andras. Through an examination of Spanish and Portuguese works, and the view that the author must have had Spanish/Andalusian origins, the study leads to the conclusion that Andrad of Seville is none other than Pedro Fernández de Andrada, author of De la Naturaleza del Cavallo, or "On the Nature of the Horse", a work in Spanish published in Seville in AD 1580.