Demeter is the great Greek Goddess of agriculture and the fertility of the earth and of women; one of Her daughters is called Despoine, a title which means 'the Mistress'. In the classical myth, while Demeter was seeking Her missing and abducted daughter Kore, Poseidon raped Her; consumed by grief and rage, Demeter dressed Herself all in black and shut Herself in a cave, for which She became known as Demeter Melaina.
The result of this rape was a daughter, Despoine, Who was worshipped by the Arkadians as their principal Deity; She was the Goddess of a mystery cult there. Given that Her true name was known only to those who had been initiated into the cult, it has not come down to us, and so She is known today by Her title.
The two were worshipped together in a shrine in Arkadia, where Their cult statue showed Them sitting together on one throne. That reminded me of an old Mykenaean ivory statuette showing two women seated together (with a small child in front) and sharing one mantle; and that in turn reminded me of the old Neolithic statuettes from Anatolia that show an apparently double-headed Goddess. They are extremely stylized; basically they are a circular body with two heads poking out. They are incised with decorative markings but are careful to include a pubic triangle to mark the figures as female.
I have taken those old images to represent the Mother Goddess and Her grown daughter; together they represent the cycle and continuity of life passed on from mother to daughter, as the daughter grows up to be the mother who gives birth to the daughter who grows up to be the mother who births the daughter who...
There is also a tablet from Pylos dating from Mykenaean times that mentions Goddesses known there as 'the Two Queens'. So I have put Demeter and Despoine side by side (Demeter is on the left) as the Mother and Her grown daughter, and I have put them in Minoan-style dress to reflect Their ancient origins.
Despoine was done as the monthly Goddess by request for January 2018 over on my Patreon; Demeter was a bit of a bonus. The original is in ink outlines in black, with watercolor and white gouache on toned paper, using the limited palette of Minoan frescoes.
This design is available on prints through Society6.