area became a vast area of grain production and cattle/sheep-grazing. The richness and abundance of these combined 'base economies' grew to such extent that Castro Verde became a regional centre of commerce and thus a crossroad of cultures within the Mediterranean area. The name origin of Castro Verde dates back to this early period, with two interpretations cited for its name. One postulates that the name was derived from the Roman Castra Castrorum and combined the verde (meaning "green") to indicate new. A more consistent interpretation is that the name was derived from Castrum Veteris, meaning the oldest castro, to differentiate it from another castro that existed on a small plateau (where the Chapel of São Martinho exists) and was abandoned during the Middle Ages. The term castro derived from the Latin castrum refers to a small military encampment or fortification, built of large rocks. Roman occupation spanned four centuries and was followed by the migration of the Visigoths (300-700 A.C.) their expulsion by the Moors (in 711), and in turn, their expulsion from the area during the Christian Reconquista. The Battle of Ourique, where Afonso I triumphed over five Moorish Kings occurred in São Pedro das Cabeças, approximately five kilometres from the village of Castro Verde, and paved the way for the creation of the Kingdom of Portugal (in the Treaty of Zamora in 1143). As the legend of the Battle describes, the battle lasted two days (between 24 and 25 July 1139) and was so excessively bloody that the waters of Ribeira de Cobres flowed the color of red. Afonso Henriques who was declared Prince of Portugal, after the Battle of São Mamede, defeated the Moorish kings (at the Battle of Ourique), and was then proclaimed King upon the victory. But, although King Afonso was able to triumph, the region was never definitely secured by the Portuguese until the regin of King Sancho II, around 1234, when the Castle of Aljustrel was captured. Later, the Royal Basilica of Castro Verde was commissioned by King Sebastian of Portugal in 1573 to mark the Christian victory over the Moors, with the walls of the central nave covered in azulejos immortalizing the famous battle. The region of Castro Verde passed into the possession of the priory of the Comenda de Santiago, and its donatários, the Dukes of Aveiro. Castro Verde continued to operate as the central administrative centre and municipal seat,