Early European portrait artists sometimes painted their contemporaries as allegories. Allegorical portraits remained popular for several centuries, as they expanded to show the female sitter as a Biblical figure, a Greek or Roman goddess, or nymph or muse in in a rustic setting. Diana is a Roman goddess of the hunt, the moon, & nature, associated with wild animals & woodland. Diana was known as the virgin goddess of childbirth & women. Diana was originally considered to be a goddess of the wilderness & of the hunt, a central sport in both Roman & Greek culture.
"... people regard Diana & the moon as one & the same. ...her name Diana derives from the fact that she turns darkness into daylight. She is invoked at childbirth because children are born occasionally after seven, or usually after nine, lunar revolutions ..." -- Quintus Lucilius Balbus as recorded by Marcus Tullius Cicero & translated by P.G. Walsh. De Natura Deorum (On the Nature of the Gods), Book II, Part ii, Section c.