A man who has seen a nymph "becomes possessed by nymphs" according to ancient Greek lore. Nymphs were embodiments of the spirit of nature, so there are many kinds—nymphs of rivers and woodlands, streams and mountains. Nereids are nymphs of the sea (specifically the fifty daughters of the old sea god Nereus), and usually are benevolent and playful, taking care with the fate of sailors. Although mortal, they live supernaturally long lives. Among the best-known nereids are Thetis, mother of Achilles, and Amphitrite, wife of Poseidon, but no specific attributes identify this one.
This nereid's head is thrown back with abandon, her lithe body in counterpoint with a sea monster that helps support the weight of the marble. Voluminous twists of fabric cross diagonally over her, contributing dynamic energy to her pose. The marble here is deeply cut, creating dark pockets of shadow that enliven the surface. She is attributed to Giuseppe Mazzuoli, who as a young man worked with Gian Lorenzo Bernini in Rome. Throughout his career of some seventy-five years, Mazzuoli generally worked in the more flamboyant baroque tradition of Bernini.