Middle Ages, the history of Portugal is inseparable from that of Spain. Present-day Portugal became a part of the Roman province of Lusitania in the 2nd century bc. In the 5th century ad control of the region passed to the Visigoths, and in the 8th century it was included in the area of Moorish Muslim conquest. In 997 the territory between the Douro and Minho rivers (now northern Portugal) was retaken from the Moors by Bermudo II, king of León, and in 1064 the reconquest was completed as far south as present-day Coimbra by Ferdinand I, king of Castile and León. The reconquered districts were then organized into a feudal county, composed of Spanish fiefs. Portugal later derived its name from the northernmost fief, the Comitatus Portaculenis, which extended around the old Roman seaport of Portus Cale .

Portugal became an independent monarchy in 1139. Its name derives from Portus Cale, a pre-Roman or Roman settlement near the mouth of the Douro River. The southern part of the Roman province of Gallaecia (now Galicia) was occupied by the Germanic Suebi in AD 411, and Portucale (Porto) was held by them. They were subdued by the Visigoths, whose state was overthrown by Muslim invasions in the 8th century. A Christian territory of Portugal was constituted in 868; it later became a county and was extended to Coimbra. Afonso Henriques assumed the title of king (1139) and annexed Lisbon. His successors took Alentejo and Algarve from the Muslims (by 1252). Portugal now includes the Madeira Islands and the Azores, first settled in the 15th century.

King Afonso III, who reigned from 1248 to 1279, completed the expulsion of the Moors from the Algarve and moved the capital of Portugal from Coimbra to Lisbon. He also began the practice of governing with the aid of a Cortes (representative assembly), which included members of the nobility, the clergy, and the citizens, and he increased the power of the monarchy at the expense of the church. His son Diniz, called the Farmer King because of his encouragement of agriculture, founded the University of Coimbra, the nation’s first university, and was responsible for the development of the Portuguese navy. In 1294 he signed a commercial treaty with England, beginning a sequence of alliances between the two countries. Diniz’s successor, Afonso IV, joined with Alfonso XI of Castile to win a major victory over the Moors at the Battle of the Salado River in 1340. In this period the royal houses of Castile and Portugal frequently intermarried, repeatedly raising the possibility that one of the kingdoms might be absorbed by the other.