Ernoul Caupain was a trouvère, probably active in the mid-thirteenth century. Two pastourelles, a chanson courtoise, and a religious poem have survived of his work, although one of the pastourelles has conflicting attributions in the two sources and probably is not his. His works are only transmitted in the trouvère chansonniers M and T.^[1] Gustav Gröber suggested that he was the same person as the Copin who judged a jeu parti between members of the literary circle flourishing in and around Arras.

Ernoul's poems have relatively long strophes of eleven, twelve, or fifteen lines. He typically uses octosyllables mixed with hexa- or heptasyllabic lines. His melodies are in the authentic G mode with strong tonal centres. They are written in bar form.