The collection begins with an address from Marie. She stresses that "anyone who has received from God the gift of knowledge and true eloquence" has a duty to use those gifts for storytelling.
She tells how ancient writers believed it virtuous to express themselves obscurely, so that readers of their work would have to study the works in depth. The belief was that, by dedicating oneself to such study, one would avoid vice and "rid oneself of great suffering." Marie considered paying homage to this tradition by translating a Latin text into French, but she decided that such endeavors had been done too often by too many others.
Thus, she has chosen to devote herself to the telling of lays that she has heard and the stories which she believes to be true. In honor of the stories, she has stayed up "late into the night" composing them into verse.
She dedicates the work to a "noble king", and hopes he will enjoy them, since that will bring her happiness.
Like the lays themselves, Marie's prologue contains a good deal of sophistication that is belied by charm, brevity, and seeming simplicity.
Most central to the prologue is an implied statement of purpose. While Marie does not explicitly contrast her goal – of relating lays that she has heard – to the classical goal of creating obscure texts that demand study, it is clear that she considers her work to be a step in a different direction. Historically, Marie's work was contemporary in its use of vernacular (French language) rather than Latin, which had for centuries been required for any serious work. What's more, her contentment with lays, narrative poems often meant for singing and derived from folk tales as much as from classical models, suggests that she intends her work to be more direct than classical work, more fit for a regular audience.
Of course, the audience for this work would surely have been aristocratic and courtly. This is not only supported by historical evidence, but also by the patron ("noble king") mentioned in the prologue. However, the fact that Marie paints the raison d'etre of the work as "simplicity" provides insight into the stories themselves. The lays that comprise her collection are concerned primarily with the theme of love, a theme that anyone can relate to. The poems are not didactic or morally consistent, and thus deserve study, but they are not inaccessible to anyone who lacks the intense discipline of classical study that she describes. While the work draws its models from classical tropes and heroic figures, the real conflicts are everyday passions and mistakes. By stressing her break from classical 'seriousness,' Marie helps us see that her intention was very much to focus on subjects that traditionally might have been considered inferior.
The prologue also provides some clues into Marie herself, useful since she interjects her perspective constantly through the lays. Firstly, she projects great confidence. Implied in the prologue is her ability to write on par with the classical masters; she just doesn't want to. Again, there is an implicit pride in a conscious choice to focus on different themes than her literary progenitors. It also, in its first lines, paints her as a storyteller of note. She implies that she herself is blessed with talent from God, and that she not only deserves attention but also is obligated to earn that attention through a proper use of those talents. This theme also mirrors the subject of many of the poems, which tend to reward lovers who love in service of others, and punish those who love solely for selfish reasons. Again, the prologue provides a touch of thematic foreshadowing. Lastly, by stressing that she has stayed up late into the night, Marie provides proactive defense against those who might try to claim her works are only unconsidered little love poems, a defense that close analysis will certainly play out as true.