This work expect to prove relations between the bookbinding of two manuscripts conserved in the Library of the University of Barcelona and the bookbinding to realise in the workshop of bookbinding of the Library of Alfonso el Magnanimous in this court Neapolitan, across over the study of this elements and architecture, and give the denomination of bookbinding mudejar neapolitan, because they are to make in this workshop or in this defect in Italy in the middle of the XV century.