We are compelled when dealing with certain matters to make our tale rather long, since we are accustomed to recite the opinions and parts of the text of certain authors who, before us, have already written about these things. We do not do this out of any pleasure at being long-winded, which great lords find boring, but because not finding such explanations in this volume would be counted as imperfection. Moreover, whoever desires to read many works of history, especially authentic and authoritative ones, will find that their writers have praised [certain] great lords and their good usages and have described the character of others as ugly and their deeds as equally wretched. Saint Augustine, whose work and authority are beyond criticism, has written like this in the book entitled The City of God. In this part of our work, following his lead, we are forced to censure some people, speaking against them in certain sections, especially as the tale of their excesses had already been broadcast by others before us in such accounts. However, their stained reputations, according to written law and evangelical doctrine, have not blemished their lineage when their descendants chose not to follow in their perverse footsteps.

We said that when the Master had besieged that town which he desired so much to take, there were faithless vassals whom he had brought with him who, by written messages and various other means, had informed the besieged defenders about his every undertaking, causing it to be in vain. Therefore, it is only reasonable for you to expect us to tell you who they were, what status they had, whether the Master knew anything about it and when and how he knew. Before we say what made them do this and make known what others first divulged, let us see immediately which men they were. Searching through all the books that make mention of these events, the accounts refer to four men: Count Pedro, Dom Pedro de Castro, Juan Alfonso de Baeza and García González de Valdés.

You have already heard of Count Pedro when we spoke of what happened to Queen Leonor when she went to Coimbra; how this Count of Trastámara, a first cousin of the King of Castile, had wanted to cast his lot with her while there, and how he had fled and gone to Oporto, and thence in the Portuguese galleys to Galicia.