Circe is the smaller of two worlds controlled by the Circean Witches (the Sisterhood of Circe), an all-female order of psyches.
The larger and more populous world nearby is named Perseis. The Sisterhood, headquartered on the smaller world of Circe, limits the technology of Perseis through its “advisory” role to the world’s various governments. Women on Perseis are tested in adolescence, and those with the talent are taken away to Circe and become novices in the Sisterhood.