A lucky discovery! The English translation of Flamenca, story by an anonymous author from the 1200’s. This is felt, by the translator, W. A. Bradley, to be the first of the early romances that was not based on an old legend. So he calls it the First Modern Novel.
There are some similarities to another story, The Earl of Toulouse, which is also on elfinspell. In this story's Modern English translation by Edith Rickert, the notes say it is based on a lost lai. Whether Flamenca is the lost lay in question, isn’t stated, but it seems similar enough to have provided a framework for it. Or the other way around.
Whatever the origin, it is an interesting story. Once again, the common plot, and character types will look familiar to us even now, showing how much more alike in taste we are to those far off people in their armor and wimples.
Read Flamenca, and Bradley’s reasons for his work yourself: