In this book, we propose a discussion that involves the concepts of legitimacy and justice applied to the context of the Courts of Coimbra of 1385 that would elect king, D. João I of Avis. Fátima Regina Fernandes is doctor in Medieval History by the University of Porto-Portugal, Master in History by the Federal University of Rio de Janeiro (UFRJ) and, Graduated in History by the University of Porto-Portugal. Titular Professor in the department and program of postgraduate studies in History by UFPR, PQ I researcher of the CNPq and founding member of the Núcleo de Estudos Mediterrânicos (NEMED). Authoress of several titles and participant of international and national research groups.