Now that we have seen the people and places which swore to uphold the treaties devised by the kings, those who would like to hear how it was carried out need to know that it happened as follows: when the priest had put on his robes, he said Mass, holding the Holy Body of Christ on a paten. Then the prelates we have mentioned, lords, grandees, noblemen, knights and squires, and likewise, the proctors of towns and cities who were present, each and every one of them by order and permission of the said king [of Castile], swore on the Sacred Host that was held before them, each one touching it with his hands, promising to comply and endeavour to do everything in their power to abide by the pledges, oaths and promises made by the aforesaid king on account of his marriage to his wife, the queen, and the treaties and agreements that had been made and signed to seal it. These were to be upheld, made to last and kept firm both by him and by the queen, his wife. Furthermore, all those present promised that they would not participate, then or at any time, in word or deed, in advice given or in any other action that would aim to obstruct or undo the aforementioned marriage.

The aforesaid King Juan, who was present, in order to give more credence to his promise that he would maintain, safeguard and fulfil all the clauses contained in the documents, gave permission to the aforesaid prelates, lords, grandees, knights, squires and nobles, and likewise, the proctors of the towns and cities, and certain people who were not present, that if for some reason he failed to uphold and abide by all the sections of the treaty which had been confirmed by oath between himself and the said King and Queen of Portugal, and each item contained in them, in the manner and with the conditions and times that were written in them, then his aforesaid subjects could and would rebel against the King of Castile and go over to the King and Queen of Portugal, to keep and fulfil the treaties and all the clauses of their chapters, and all the things which were stated in them.