What is the summary of 'my last dutchess'?

Answer 1

The speaker of the poem is a duke, and he is talking about a painting of his dead wife, who was young and pretty. (A woman who marries a duke becomes a duchess.) It turns out that the duke killed his wife! He did it because she was nice to everyone -- not just him. He was jealous, even of her smiling at people.

The twist at the end is where you realize that he's talking to a messenger who is arranging the duke's marriage to another young, pretty girl. His NEXT duchess. He hopes that this new girl will work out better than the last one.

Also, toward the end of the poem the poet talks about a statue of Neptune and how he tamed a sea horse and how it was thought to be rare in its beauty. This is a metaphor for how he tamed his wife by having her killed, calling himself Neptune and his last wife a seahorse whom once was elegant but is now tamed and put on display for him to look at whenever he wants.