The serpent biting its tail symbolises Eternity. The crowned figure of Janus holds the fleece from which the Three Fates draw out the thread of life. The hooded figure is Demagorgon who receives gifts from Nature, from whose breasts pours forth milk. Seated at the entrance to the cave is the winged figure of Chronos, who represents Time. This painting is one of a group of 10 \'modelli\', or elaborated oil studies, made in preparation for the fresco projects that Giordano created for the Palazzo Medici Riccardi in Florence. This painting is connected with the ceiling of the Galleria.