After they had been there for two weeks, the king and the duke departed with their army and went to camp at Villalobos, a strongly-walled town, like the others belonging to that same Álvaro Pérez de Osorio. On one side the moat had a great deal of water, and on the other it was entirely dry. There were men-at-arms inside the town, as well as men from other companies, but there was no renowned captain who had the authority to lead them.

Preparing to attack it, the king ordered that, to fill in the dry moat to a level whereby they could cross over it, a certain amount of the hay that was brought in for the camp should be thrown in. This was done over three days, so that all should be ready when the time came to attack.

For the protection of the hay and those who were transporting it, the king sent Martim Vasques da Cunha, his brothers, and other noblemen with a few soldiers. When the pack-animals and many of those who were going to guard them left the camp, Martim Vasques and his brothers Gil Vasques and Lopo Vasques, as well as [Sir John] Mauburney, Lourenço Martins do Avelar and João Portela, along with other squires and knights, about eighteen in all, happened to fall behind. Talking among themselves, they rode along very slowly, because there was a dense mist that day, and the morning light was not yet very clear. Failing to realise in which direction they were going, on account of the poor visibility, they missed their way. When they were a full league from the camp, they ended up by the stream [Cea] that flows from Mayorga, where there were 400 Castilian lances and many foot soldiers camped in a grove of elm trees where they had slept that night. Their captains were Don Fadrique, Duke of Benavente, bastard brother of the king, Álvaro Pérez de Osorio, Ruy Ponce de León, and others. When they saw them so close at hand, recognising that they were Portuguese, they began shouting, ‘Kill, kill! For Castile, Castile!’ Seeing themselves in the midst of such great danger, the Portuguese started to shout loudly ‘Saint George, Saint George! For Portugal, Portugal!