"The Eve of St. Agnes" is a romantic poem written by John Keats. The protagonist of the tale is Porphyro, the young man who loves Madeline, who belongs to an enemy clan. Although he is the third character readers meet in the poem and doesn't appear until stanza 9, he is the one whose conflict, goals, and actions drive the plot. Madeline also has goals and desires, but hers are less overt. She hopes only to dream of her beloved by following the St. Agnes's Eve custom of going to bed without supper and following the proper ceremonies.

Porphyro is much more action-oriented. He sneaks into Madeline's house even though there are many at the gathering who would do him harm. He persuades the nurse to hide him in a closet in Madeline's room. When Madeline appears again, readers view and hear her mostly from Porphyro's vantage point. He nearly faints from watching her say her prayers, gazing "upon her empty dress," and hearing her breathing slow as she falls asleep. He then lays a banquet for her and wakes her by playing a tune on her lute. He invites her to run away with him, and she agrees.

Because Porphyro is the actively wooing partner in the romance, it is appropriate to name him the protagonist of the poem.