You have heard how, about two months ago, thirteen galleys departed from Lisbon and went to the city of Oporto, so that all of them, along with the naos and galleys of that town, could come and do battle with the fleet of the King of Castile after he laid siege to the city. So that we may see better all that was done after they arrived there, let us first read the three following chapters concerning what happened before their arrival.

It is important for you to know that, when the King of Castile had Lisbon surrounded, as we have said, and the towns in the Minho already mentioned came to his side, Don Juan [García] Manrique, the Archbishop of Santiago, joined with many Portuguese and Castilian troops to raid and ravage that entire district wherever they had declared loyalty to the Master. The Portuguese captains who went with him were the following: Lope Gómez de Lira, João Rodrigues Portocarreiro, Fernão Gomes da Silva, Aires Gomes the Elder, Martim Gonçalves de Ataíde, Vasco Gil de Fontelo, and Gonçalo Peres Coelho.

The Galician captains were Fernán Pérez de Andrade, Bernardo Yáñez de Santiago, García Rodríguez de Valcarce, Martín Sánchez de la Marina, Pedro Álvarez, Pay Sorredea, Juan Rodríguez de Biedma, Gonzalo Mariño, and others. In all, they brought about 700 lances and 2,000 foot soldiers, all hand-picked men, well-prepared to fight.

Also active in that district was a Castilian knight called Fernando Alfonso de Zamora, a most high-ranking man, accompanied by eighty very good squires on horseback, both Castilians and others; he, however, moved separately and with guile, as follows: when he came to towns loyal to Portugal, he said that he was on the side of the Master; when he came to those loyal to Castile, in a few words he made them understand that he was on their side. In that way he moved about with his men, swallowing up and laying waste the land, without opposition from anyone. With this deception he came to Santo Tirso de Riba de Ave with his men, and stopped there, taking his ease, very confident that nothing bad could happen to him, and without setting any guard.