Demeter, the Greek Goddess of grain and fertility who according to myth taught humanity agriculture, is often associated with the Empress. It's interesting to compare the image of her above, taken from the 19th century work Dr. Vollmers Wörterbuch der Mythologie aller Völker, to the RWS Empress.

The throne, scepter, and grain are elements present in both images. They communicate this archetype's dominion over growing things, and represent a figure who is both maternal and authoritative.