The last panel illustrates the myth of Apollo and Daphne, one of the most well known and loved myths of Antiquity. There are no inscriptions to explain the action but no one would have had any difficulty in identifying the protagonists. The nymph Daphne, daughter of the river Peneus, had sworn eternal chastity. The god Apollo, however, fell in love with her and after failing to convince her to consent to his wishes, tried to catch her by force. “Thus the god and the nymph sped on, one made swift by hope and one by fear; but he who pursued was swifter, for he was assisted by love’s wings” (Ovid, Metamorphoses, Book I). In their mad chase they reached the waters of Peneus and just as Apollo was about to catch his victim, Daphne prayed to her father for help. All of a sudden, her feet remained rooted to the ground, her body was covered by bark, and her arms and hair turned into branches and leaves. She had, in fact, turned into a laurel tree, a plant that in Greek still bears her name, Daphne. Apollo continued to love Daphne even after her metomorphosis. For this reason he chose the laurel to be his sacred tree, and his garlands were henceforth made with its leaves. He also granted that just as his head was ever young, so should the tree always be green and never lose its foliage.
On the mosaic we see the moment when Daphne is rooted to the ground, her legs turning into a tree. She is standing next to her father Peneus, represented as a river deity in the fashion we have already seen in the panel of Pyramos and Thisbe. To the right, Apollo, still running with bow in hand, points with amazement at the transformation. His arrows, still in the quiver, can be seen behind his right shoulder.