On April 6, 1384, the Portuguese forces of John of Aviz, led by the general Nuno Álvares Pereira, won a significant victory over a Castilian expeditionary army at the Battle of Atoleiros. The battle was an early success for the Portuguese in the 1383-1385 Crisis, demonstrating that the Castilian forces could be defeated and bolstering Portuguese morale. The victory also showcased the effectiveness of Portuguese defensive tactics and the leadership of Nuno Álvares Pereira, who would become a national hero.

The Battle of Atoleiros was celebrated in Portuguese chronicles and ballads that portrayed it as a miraculous victory against overwhelming odds, a theme that resonated deeply in the Portuguese literary tradition. The battle was later immortalized in the epic poetry of the Portuguese Renaissance, most notably in Luís de Camões's Os Lusíadas, which drew upon the events of the crisis as part of a larger narrative of Portuguese national destiny. The battle's legacy also influenced the popular poetry of the 'romanceiro' tradition, which preserved the memory of the conflict in oral form for centuries.