One of my favorite William Butler Yeats's poems is his "Leda and the Swan." In Greek myth, Zeus, in the form of a swan, seduces Leda, thus fathering Helon Troy (whose abduction started the Trojan War) and Clytemnestra, (Agamemnon's wife and murderer). Yeats thought of Zeus's appearance to Leda as a type of annunciation, like the angel appealing to Mary. Mary and Leda are both theotokos (god carriers).
A sudden blow: the great wings beating still
Above the staggering girl, her thighs caresses
By the dark webs, her nape caught in his bill,
He holds her helpless breast upon his breast.
How can those terrified vague fingers push
The feathered glory from her loosening thighs?
And how can body, laid in that white rush,
But feel the strange heart beating where it lies?
A shudder in the loins engenders there,
The broken wall, the burning roof and ...