The meaning and subject of the painting depicting a nude woman seen from the back in a dark bedroom with a man asleep on a bed and two onlookers behind a half open door are still a matter of contention among art historians.

The sleeper in his dream or because he has woken up has upset the pedestal table near his bed, causing a candle stick and a pot (or jug) to fall to the floor.

The male spectator is carrying a lit candle which casts upon his head and that of the woman a warm light, and causes the shadow of his hand to fall on the panel of the open door.

[4] Erwin Bielefel argued that the painting most likely depicts a story written by Phlegon of Tralles for the Roman Emperor Hadrian, to which Jordaens may have had access through a translation or a contemporary adaptation.

According to Bielefeld, Jordaens' Nocturnal appearance follows closely Phlegon's story and depicts the decisive moment or climax of the ancient tale.

[5] Julius S. Held disagreed with Bielefeld by pointing out that the painting differs in many ways from the story of Marchete and Philinion told by Phlegon.

Held suggests that the composition possibly represents the story of Alcyone and Ceyx as told by the Roman poet Ovid in his Metamorphoses.

In the print Morpheus, the god of dreams, appears in the shape of her dead husband Ceyx to Alcyone lying at night on her bed.