João Afonso Pimentel, who, as we said, held Bragança, chose not to join the king and refused to declare allegiance to him despite the arguments which the constable put before him, as we have related. In time, however, he realised that the king had regained Chaves despite Martim Gonçalves's resistance. He realised also that the King of Castile, though informed about the siege of Chaves, had sent a message to Martim Gonçalves during the truce, stating that he did not care to go and seek to raise the siege, a decision that had forced Martim Gonçalves to abandon the town after great travail and with little personal honour. With these factors in mind, he reflected that the same fate could befall him too and considered that the King of Portugal would continue to recover his kingdom in this way, step by step, especially as several people were already snarling that Bragança would also be besieged. Accordingly, to protect his honour and standing, he decided to enter into a parley with the King of Portugal with a view to his holding Bragança with all that it contained, and to his declaring his allegiance to him.

While the negotiations were in progress, many Castilian muleteers and merchants happened to pass through the Bragança area, bound with their merchandise for Saint James's feast-day in Santiago de Compostela in Galicia, which was due in July. Since Bragança had declared for Castile, they were confidently travelling that way, by which they intended to come back. Maliciously, João Afonso gave them all a warm welcome, making it clear that, if they came back that way, he would be very pleased and would treat them honourably and buy some of the goods they brought with them. Believing matters to be as he said, they all returned the same way that they went, bringing with them more money from what they had sold than any remaining goods. However, João Afonso had them all arrested, seized their pack-animals and everything they had with them, and held prisoner those whom he saw fit. He then declared his allegiance to Portugal and went to join the king.