The subject of this painting has been taken from the 12th fable of Book XIII in Ovid's Metamorphoses which tells the story of the Cyclops Polyphemus' jealousy over Galatea's love for the shepherd Acis. Gustave Moreau's interest in the theme was revealed by two photographs that he hung in his dining room: one of Raphael's Triumph of Galatea and the other of Sebastiano del Piombo's Polyphemus.
Here, far from illustrating the story, Moreau has gone no further than the first line: "Here is a terrible giant who loves a beautiful nymph". He gives a personal, modern, magical interpretation of the pagan myth, rejecting the anecdotal and concentrating on the opposition between exquisite beauty and hideous ugliness, beauty and the beast, love and disdain. His composition stages a struggle between shadow and light, mineral and liquid, good and evil. Moreau's Polyphemus is nevertheless not an ogre, but a melancholy being, lost in one-eyed contemplation of the inaccessible woman. Galatea, who has taken refuge in a cave too narrow for the giant to enter, is a pearl gleaming in its setting. The change in scale between the two figures is repeated between Galatea and the tiny nereids almost invisible in the lacework of aquatic plants and coral... This vegetation looks supernatural but was derived from drawings meticulously copied from a book of marine botany in the Museum d'Histoire Naturelle, where Moreau had registered as an unofficial student in 1879. The rubbed, scratched texture of the oil paint gives the work a precious, enamelled look. The Salon of 1880 was the last in which Moreau took part. Galatea was a triumph there and marked the height of his career.