At the other end of the Mediterranean from the growing Ottoman empire, the consolidation of the Christian-ruled states in Iberia reached a critical point during the fifteenth century, with Portugal becoming the first to turn to the creation of an overseas dominion, while the unification of the kingdoms of Castile and Aragon in the last third of the century laid the foundations for the emergence of what would become, in the following century, the dominant western European power. An initial stepping stone for the development of this potent force was the conquest by Ferdinand and Isabella of the last Muslim kingdom in Iberia. Granada succumbed to a sustained attack that reveals much about siege warfare at the end of the fifteenth century.

Portugal in North Africa

Siege of Ceuta

The Muslim states of the North African coast had become incapable of uniting or of finding sufficient resources to match those of their expanding northern neighbours. There had been several events since the beginning of the century to predict the outcome. Whereas the world chiefly knows the Portuguese prince Henry through his nickname of the “Navigator”, his first claim to notice arose from the small kingdom's successful capture of Ceuta in 1415. The chronicles assign a significant part to King John (Joao) I (1385–1433)'s brood of young sons in the decision to attempt this conquest, from where it was easy for an effective navy to control the straits. It does seem that the presentation of this as being a contribution to the (otherwise dormant) anti-Islamic crusade may have been a genuine reason for the attempt. It was for all that an act of simple, unprovoked and undeclared aggression. John would rather have attacked Granada, but was hindered from doing so by the rather inconvenient truce then in place between that kingdom and Castile.

King John planned a meticulous operation, because it was no easy thing to convey an army by sea to capture a strongly-walled city in completely hostile territory. His spies surveyed Ceuta under cover of a diplomatic voyage to Sicily, reporting back that they thought it could be taken.