Lineage of the Janus god metaphor in condensed matter

Five years ago, Antoine Georges and collaborators invoked the metaphor of the greek god Janus to represent the "two-faced" effects of Hund's coupling in strongly correlated metals.

I wondered where they got this idea from: was it from someones rich classical education?
In the KITP talk, I recently watched online, Antoine mentioned he got the idea from Pierre de Gennes.

In his 1991 Nobel Lecture, de Gennes said

the Janus grains, first made by C. Casagrande and M. Veyssie. The god Janus had two faces. The grains have two sides: one apolar and the other polar. Thus they have certain features in common with surfactants. But there is an interesting difference if we consider the films which they make —for instance, at a water-air interface. A dense film of a conventional surfactant is quite impermeable. On the other hand, a dense film of Janus grains always has some interstices between the grains, and allows for chemical exchange between the two sides: "the skin can breathe. " This may possibly be of some practical interest.

Here are some images of "Janus particles".