The poem very clearly alludes to the mythology surrounding Circe, an goddess/enchantress most famous for her appearance in Homer's Odyssey.
The Odyssey tells the story of Odysseus, King of Ithaca, who is trying to return home by sea after fighting in the Trojan War. In his travels, he and his men come upon Aeaea, the island where Circe lives with various "nereids and nymphs" (minor Greek nature deities who took the form of beautiful young women).
In Homer's tale, Circe turns Odysseus's men into pigs and then tries to seduce Odysseus to the same end. Odysseus, however, having been warned by Hermes (messenger of the gods), doesn't fall for Circe's tricks and compels her to turn his men back into human beings. After this, Circe and Odysseus become lovers, and Circe bears Odysseus two sons. She then offers him valuable advice that allows him and his men to sail safely home.
The end of this poem alludes to the arrival of Odysseus and his men on Aeaea, but the poem doesn't name them outright. After all, this is a reimagining of the classic myth, and in this version, Circe's story is the one that matters. Rather than being a small, supporting character in the male hero's journey, this Circe is at the center of her own narrative.