C.S. Lewis studied the Roman de la Rose as a major example of courtly love literature in The Allegory of Love.
The Roman de la Rose is a long medieval French poem presented as an allegorical dream vision. It was begun by Guillaume de Lorris and later continued by Jean de Meun. Lewis used it as part of his examination of how allegorical representations of love developed in medieval European literature.
The poem’s two parts differ in tone and intellectual emphasis. Guillaume de Lorris began the work in the thirteenth century, while Jean de Meun expanded it later with a much longer continuation. This authorship history makes the Roman de la Rose especially important for literary historians.
Lewis’s book also discusses English and European writers, including Chaucer and Edmund Spenser. Beowulf, Dante’s Divine Comedy, and The Canterbury Tales are all major medieval works, but they are not the specific central example requested here.