The Struggle for Portugal’s Independence (1112–1128 CE)

The death of Alfonso VI of León plunges his kingdom into civil war, with Aragonese, Galician, and Castilian barons vying for control. During this period of instability, Count Henry of Portugal wisely remains neutral and gradually withdraws from his feudal obligations to León.

Teresa’s Rule and Conflict with Alfonso VII (1112–1127)

Upon Henry’s death in 1112, his widow, Teresa, inherits the County of Portugal. Initially, she follows her late husband's policy of nonalignment.

However, once Alfonso VII emerges victorious in the struggle for the Leonese crown, he seeks to assert his suzerainty over Teresa, his aunt, and her Galician consort, Fernando Pérez de Traba.

Teresa refuses to do homage to Alfonso VII, leading to a six-week war in 1127, after which she is forced into submission.

Afonso Henriques Rebels Against Teresa (1128)

As Teresa’s fortunes decline, many of her Portuguese barons, who fear the loss of their power and independence, turn against her. They align themselves with her son, Afonso Henriques, who has recently armed himself as a knight.

On July 24, 1128, at the Battle of São Mamede near Guimarães, Afonso Henriques defeats his mother’s forces and expels her to Galicia, where she later dies in exile.

This victory grants Afonso Henriques full control over Portucalense, known in the vernacular as Portugal, paving the way for his later declaration of independence from León and the establishment of Portugal as a sovereign kingdom.

Afonso Henriques' Early Ambitions and the Battle of Cerneja (1137 CE)

Having seized control of Portugal as a young and ambitious leader, Afonso Henriques is determined to break free from León and establish an independent kingdom.

The Invasion of Galicia and the Battle of Cerneja

To assert his power, Afonso Henriques invades Galicia, confronting the forces of Fernando Pérez de Traba and the Galician barons. He achieves a decisive victory at the Battle of Cerneja, further strengthening his position.

Conflict with Alfonso VII and the Treaty of Tuy (1137 CE)

In response to Afonso’s growing defiance, Alfonso VII of León, who has recently proclaimed himself Emperor of Spain, orders his Galician vassals to launch an offensive against Portugal.

At the same time, Muslim forces in the south, recently reinforced by the Almohads from Morocco, pose a serious threat to Portuguese territories.

Faced with pressure on two fronts, Afonso Henriques chooses to negotiate peace. In 1137, he meets with Alfonso VII at Tuy, where they agree to a truce, allowing Afonso to secure his rule over Portugal while preparing for future challenges to his sovereignty.