BATTLE OF ATOLEIROS

The 'Battle of Atoleiros' (pron. IPA []) took place on 6 April 1384, between a Portuguese force and a punitive expedition from Castile sent by John I. The battle took place near the population centre of the same name in Alentejo. It was the first major battle of the 1383–1385 Crisis.
Nuno Álvares Pereira had been chosen to protect the frontier in this area, amid fear that a Castilian force could enter Portugal here. He left from Lisbon, adding to the strength of his forces on his way to Atoleiros. As he approached the Castilian army, the Castilians sent an emissary to the Portuguese army, attempting to dissuade it. The Portuguese refused, and when the Castilians advanced to meet them, the Portuguese formed a defensive square. In the short battle that followed, the Castilian cavalry was unable to break the Portuguese formation, and withdrew.