[1] In the aftermath of the Portuguese victory at the Battle of São Mamede (1128), the Portuguese count, Afonso Henriques, began a concerted effort to establish his independence, growing increasingly uncomfortable sharing power with his mother, Countess Theresa, who was supported by the Galician nobility and her lover, Fernando Pérez de Traba.

The Chronica Adefonsi imperatoris notes that "prior to this, the Portuguese monarch had come to Galicia several times, but always he had been driven back by Fernando Pérez and Rodrigo Vélaz and other Galician leaders.

"[2] Between 1137, when he signed the Treaty of Tui, recognising Alfonso VII of León as his suzerain, and 1139 Afonso declared himself King of Portugal.

The anonymous author of the Chronica, who attributes their defeat to their sins, recounts the expedition in one paragraph: Once more Alfonso, King of Portugal, gathered his army and went to Limia.

When this news reached Galicia, Fernando Pérez and Rodrigo Vélaz and other of the Emperor's Galician nobles were summoned immediately.