Once these weddings were thus concluded as we have described, there was in the year immediately following, 1376, another marriage arranged by King Enrique and the King of Portugal, namely that Don Fadrique, the Duke of Benavente and son of King Enrique and of a lady called Doña Beatriz Ponce, would marry Princess Beatriz, the first-born child of King Fernando and Queen Leonor. Once all necessary documents had been signed, King Fernando called a meeting of the Cortes to enact the betrothal. It was held in the town of Leiria in the month of November in the presence of his brothers Prince João and Dom João, the Master of the knightly Order of Avis, and the counts, noblemen, prelates, knights and squires and many other people, representatives of the town communities. All had been especially summoned for the princess's betrothal and in order to acknowledge her as queen and lady of the kingdoms of Portugal and the Algarve and to do homage to her. When all the people were thus brought together, the king ordained that on the twentyfourth of the same month they should perform the betrothal ceremony. Thus it was indeed that Fernán Pérez de Andrade, as proctor for King Enrique and Don Fadrique his son, received Princess Beatriz who was present in person, as Holy Church ordains, as the wife of Don Fadrique, and she received him as her husband at the hands of his proctor.

The next day, all the lords and people who were there, whom it befitted to do this, promised fealty and did homage at the hands of the princess's proctors, Dom Álvaro Gonçalves, the Prior of the Hospitallers, and Enrique Manuel de Villena, the Lord of Cascais, and at the hands of the aforementioned Fernán Pérez, swearing that if the king died and did not leave a legitimate heir they would take the princess as their queen and her husband as their king, as long as they had truly consummated their marriage, and unless King Fernando died leaving Queen Leonor pregnant, and she gave birth to a son. If King Fernando died before the couple were of the right age to consummate their relationship, then Queen Leonor would rule the kingdom in the meantime, or whosoever King Fernando might name in his will would do so.