Cross-referencing - Oral tradition

Some of Fernão Lopes's cross-referencing techniques denote the still-prevailing influence of the oral tradition in the mid-fifteenth century. See the examples below:

1.     "You are all listening, yet no-one asks, after Nuno Álvares headed into the Alentejo, and these things that we have related were done, what the Master was doing in the meantime in Lisbon, or on what he was spending his time for the defense of the realm and the city.  Since no-one asks about it, we want you to know that after the Master took his leave of Nuno Álvares in Coina, as you have heard..." [João1, ch 109: 1-9]