An allegorical decorative panel, depicting the assembly of the gods on Mount Olympus. Apollo, in his personification as the all-seeing, all-knowing sun god is shown riding in his chariot, top right. This is pulled through the clouds by two horses rather than the usual four and some under-painting indicates that the artist changed the positioning of the horses. Apollo, also representing truth, is surrounded by brilliant light. As the guardian of man he stands for the rational, civilized side of man's nature and his attribute of a lyre is held by a putto sitting on a cloud below him.

Cast in shadow, top left, is Apollo's twin sister the virgin moon goddess Diana, representing chastity and acting as the guardian of women. Below the twins is a rainbow positioned diagonally across the canvas. An unclothed female figure reclines along it with her right arm raised. This is Iris who, in the form of the rainbow, descended to earth as a messenger of the gods. In a horizontal line below her are various female and male figures, some of which represent the Muses, Apollo's companions and goddesses of creative inspiration in the arts, together with winged male figures. Their positioning divides the canvas between the sky above and the crowded cloudscape below. Although the presence of the winged male figures is problematic they can be seen to stand for envy, and deception.

Clio, the Muse of history, and Urania the Muse of astronomy with her attribute of a globe, are on the left. On the right is Erato the Muse of lyric and love poetry holding a triangle, with Calliope the Muse of epic poetry holding a trumpet. Below them a group is positioned around the central seated figure of Jupiter, the supreme ruler of the gods and mortals, and the chief of the twelve Olympians. As the god of the sky he empowers all.

The painting shows him representing the god of many loves, who deceives women both mortal and divine. With his attribute of an eagle, his messenger, by his feet he enforces the main message of the painting. His daughter Minerva, another virgin goddess, is shown springing fully armed from his head. She wears a breastplate and holds a shield, and stands for wisdom, chastity and the defence of just causes. Beneath Jupiter and cast in shadow is Juno, his betrayed wife, wearing a crown and looking up at him, her attribute of a peacock by her side. She is shown pushed to the background, angry and scheming, and she wears her attribute of a crown and magic girdle borrowed from Venus to make her appear more desirable. She holds a sceptre which is traditionally surmounted by a cuckoo as the symbol of a deceived spouse. Above Juno is the semi-naked form of the reclining Venus, the goddess of love and fertility, with her son Cupid, the god of love, positioned directly above.

On the foreground to the right is the naked form of Vulcan, the god of fire and the lame blacksmith of the gods, looking up towards Jupiter. He was the son of Jupiter and Juno and was married to Venus, who made a cuckold of him. That he was crippled from birth is indicated by his awkward positioning in the painting, together with the long spar or crutch which he holds over his right shoulder. Above him and slightly to the left is a semi-clothed female form wearing a crown which may indicate Cybele, the earth mother who ruled over all nature. Next to her, on the right and holding a sheaf of corn, is Ceres, personifying earth's abundance. Her attribute of a sickle is shown held by two putti below Vulcan. Looking down on Ceres and Cybele, and to the right of Minerva, is Mercury, Jupiter's son and winged messenger. He wears a petasus or winged hat and holds his caduceus or magic wand, with two snakes entwined around it.

In allegory Mercury also personified eloquence and reason, which echoes ideals of learning and reinforces the idea - also established by the presence there of Apollo - that the right side of the painting stands for man's rational side, while the left represents his darker aspects. Jupiter, hovering between the two manifests both the light and the dark elements of man. Thus there are several themes running through the painting which can be seen as an allegorical manifestation of the conflict between the passions, with chastity, wisdom and goodness overcoming lust. Apollo and Mercury stand on the side of reason against the passion of Cupid, Venus and Vulcan, with conflict implied by the central positioning of Jupiter surrounded by duplicity. It was usual in such allegories for several themes to run concurrently and painting also represents the deceit and cuckolding enacted by men and women, here in the guise of gods and goddesses. It is notable that only three of the four classical elements are present, with Juno personifying air, Vulcan fire, and Cybele earth: Neptune, personifying water, is absent and he may have been the subject of a panel to himself.

A border has been painted down the two long sides of the canvas and this implies that it was probably part of an architectural scheme for a room, perhaps to be positioned on a pier, the wall between two windows. Symmetry is present throughout the image, light and dark, male and female, Juno and Vulcan cuckolded respectively by Jupiter and Venus. Thornhill was a portrait and history painter, the most successful of decorative painters of interiors of the English school, and the first native British artist to be knighted (1720).