What imagery is used in Milton's sonnet Methought I saw my late espoused saint

As he often does, in this sonnet Milton combines classical imagery with that of Christianity in recounting a vision, or dream, of his wife's return from the dead. It is all the more poignant because of Milton's blindness and the image of his wife, and all other sight, vanishes when he awakens: "I waked, she fled, and day brought back my night."
Milton creates an image of his late wife as Alcestis. In Greek mythology, Alcestis is the wife of King Admetus, who is sentenced to death for having offended the goddess Artemis. Alcestis then offers to take his place in the land of the dead. She herself is rescued from death by Heracles, to whom Milton refers as "Jove's great son," Jove being, of course, the equivalent in Roman mythology of Zeus.
Milton imagines his resurrected spouse as both a ghostly white specter and as a bride, saying her face is veiled. She is also a kind of Christ figure, returning from the dead to save Milton. Though it is not made explicit, the myth of Orpheus is also a kind of subtext to this poem as well. Orpheus is allowed to bring his wife Eurydice back from the dead, on condition that he refrain from looking at her face as he leads her from Hades back to earth. When Orpheus is unable to refrain from gazing upon her, Eurydice vanishes and is returned to Hades. Similarly, in Milton's sonnet, the moment his vision of his late wife moves to embrace him, she vanishes, and Milton then awakes into the day, which for him is totally dark due to his blindness.