Alfonso VII and the Portuguese Struggle for Independence (1126–1128)

Upon ascending the throne of León and Castile in 1126, Alfonso VII demanded that his aunt, Theresa, Countess of Portugal—the illegitimate daughter of Alfonso VI—swear fealty to him as his vassal. Theresa, however, refused, asserting her authority over Portugal and seeking greater autonomy.

Alfonso VII's Invasion of Portugal (1127)

In retaliation for Theresa’s defiance, Alfonso VII launched a military campaign against Portugal in the spring of 1127. The invasion weakened Theresa’s position, shifting power toward her son, Afonso Henriques, the rightful heir of Henry of Burgundy, Count of Portugal. With Alfonso VII’s trust in Theresa eroded, Afonso Henriques emerged as the true power in Portugal, while his mother fell under the influence of her Galician lover, Ferdinand Pérez de Trava.

Afonso Henriques and the Portuguese Secession (1128)

A bitter conflict erupted between mother and son, as both sought to control the county. However, only Afonso Henriques’ supporters—comprising the nobility of the main Portuguese cities, the local clergy, and much of the population—were committed to achieving full independence from León.

In 1128, in response to mounting pressure, Afonso Henriques led a decisive campaign against his mother and her lover, defeating their forces and seizing control of Portugal. With his victory, Portugal became de facto independent, marking a crucial turning point in the county’s history.

The Rise of Prince Afonso (1129)

The following year, Afonso Henriques formally proclaimed himself Prince of Portugal, setting the stage for the kingdom’s eventual sovereignty.