It did not please kings in ancient times that the lords and noblemen of their kingdoms married their children to the great lords of neighbouring lands without the king's permission and consent, fearing that such a bond and alliance, as ensued from this kinship, could at some time give rise to disorder contrary to their interests. According to this rule the very wise and discreet Nuno Álvares Pereira, the Constable of Portugal, having a grown-up daughter called Dona Beatriz who was of marriageable age, was solicited by certain Castilian lords and noblemen over the matter of her marriage. Very respectfully, the constable went to his liege lord and king, as was his custom, and showed him the letters that had been sent to him about this, asking the king to graciously give him permission for such a matter.

The king deferred making a decision on this, telling him that it would please him very much that all honour and good fortune should come to his daughter. However, the constable should not be in too much of a hurry because it might so chance that God would bring her another better and more honourable marriage than those offers that had been sent to him. The constable deemed it a great favour to receive such an answer from the king.

Thus the matter kept being deferred until that time when the constable was with the king in Leiria. With the king also was that illegitimate son of his called Dom Afonso, whom he had fathered before he was married, as we said when we listed his children. They arranged the marriage, and [the king] confirmed it, of this Dom Afonso, the king's son, with the daughter of the constable, which gave the constable great joy. Besides her hand in marriage, the latter gave the groom the county of Barcelos with the lands of Penafiel de Bastuço, and Montalegre with the land of Barroso, and Chaves, Guimarães, Baltar, Arco de Baúlhe and certain estates that he had in the Minho, along with other income. Since he gave the county of Barcelos to the king's son, he petitioned him to graciously make the groom the count of that place. This was because the king had promised that for as long as he lived he would not create another count in Portugal, as you have heard.