On October 30, 1340, the combined forces of Castile and Portugal, led by Alfonso XI and Afonso IV, defeated a Marinid-Granadan army at the Battle of Río Salado near Tarifa. This was a decisive Christian victory that ended the Marinid dynasty's ambitions in the Iberian Peninsula. The battle secured Castilian dominance over the Strait of Gibraltar for the next century.

The Battle of Río Salado was commemorated in numerous Castilian and Portuguese poetic works, cementing Alfonso XI's reputation as a warrior-king. It became a central theme in the 'Romancero' and inspired poems and chronicles that celebrated the triumph of Christian arms. The battle's significance was also noted in later national epics, such as Camões' 'Os Lusíadas', as a high point of Iberian military prowess.