Kingdom of Portugal, National Consolidation

A period of national consolidation followed, during which Afonso III moved the capital of Portugal from Coimbra to Lisbon. Formerly a provincial outpost, Lisbon began its transformation into the political and economic center of the new nation. Afonso began the practice of governing with the aid of a cortes (a representative assembly), which included members of the nobility, clergy, and citizenry, and he asserted the power of the monarchy to regulate property owned by the Catholic Church. His son Diniz extended the kingdom’s power by nationalizing the wealthy military religious orders and seizing their assets. In 1290 Diniz founded what later became the University of Coimbra, Portugal’s first university, and Portuguese replaced Latin for official use. Diniz encouraged agriculture and founded the Portuguese navy, planting the royal pine forest at Leiria to promote shipbuilding. Portugal’s land borders were formalized in the 1297 Treaty of Alcanices with Castile, and they have remained largely intact up to the present day.

Diniz’s successor, Afonso IV, joined with Alfonso XI of Castile to defeat the last major Muslim invasion in 1340, at the Battle of the Salado River. 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. Internally, Portugal endured great hardship in the mid-14th century. A series of devastating earthquakes struck Lisbon, and the Black Death, an outbreak of bubonic plague, ravaged the Portuguese population in 1347 and 1348. Much of the country’s farmland lay fallow, and many people starved. Ferdinand I, who inherited the throne in 1367, took measures to encourage food production, including the promulgation of a decree that required landowners to cultivate unused lands and those without occupations to work in the fields. He also promoted maritime trade and the construction of larger ships.

The death of Ferdinand I in 1383, the last legitimate descendant of Henry of Burgundy, precipitated a civil war in Portugal. Ferdinand’s Castilian widow, Leonor Teles, assumed the regency. However, many Portuguese opposed the move, fearing Leonor would claim the crown for Castile and Leon. Her main rival was Ferdinand’s illegitimate half brother, John I, who was backed by Lisbon’s wealthy merchants. Leonor, supported by most of the landed nobility, called on the king of Castile and Leon for help. John raised an army and successfully defended the kingdom against attack. In 1385 John defeated Castile and Leon decisively in the Battle of Aljubarrota and secured the Portuguese throne. The battle was won with the assistance of English archers and helped establish the independence of Portugal. In 1386 England and Portugal allied themselves permanently by the Treaty of Windsor, initiating a friendship pact that would last for centuries.