Loosely based on historical events involving Alfonso, the Duke of Ferrara, who lived in the 16th century, My Last Duchess provides a classic example of a dramatic monologue, the revelation of the Duke’s character being the poem’s primary aim.
In My Last Duchess, the combination of villain and aesthete in the Duke creates an especially strong tension. What interests us more than the Duke’s wickedness is his immense attractiveness. His conviction of matchless superiority, his intelligence and bland amorality, his poise, his taste for art, his high handed aristocratic manners - all these qualities overwhelm the envoy, causing him, as well as the reader, apparently to suspend judgment of the Duke. We are busy trying to understand the man who can combine the connoisseur’s pride in the lady’s beauty with a pride that caused him to murder the lady rather than tell her in what way she displeased him, for in that ‘would be some stooping; and I choose/ Never to stoop.’ The duke’s paradoxical nature is fully revealed when, having boasted how at his command the Duchess’s life was extinguished, he turns back to the portrait to admire of all things its life-likeness, ‘There she stands/ As if alive’.
The next lines produce a series of shocks. For it is at this point that we learn to whom he has been talking, and he goes on to talk about dowry, even allowing himself to murmur the hypocritical assurance that the new bride herself and not the dowry is of course his object. Then, there is the lordly waiving of rank’s privilege as the duke and the envoy are about to proceed downstairs and then there is a perfect all-revealing gesture of the last two and half lines when the Duke stops to show off yet another object in his collection. The possessive egoist counts up his possessions, even as he moves towards the acquirement of a new possession, a well dowered bride; and most importantly, the last duchess is seen in final perspective. She takes her place in one of a line of objects in an art collection. The duke has taken from her what he wants, her beauty and thrown the life away and we watch in awe as he proceeds to take what he wants from the envoy and by implication form the new duchess.
During the duchess' life, the duke explains, his wife would offer that beautiful smile to everyone, instead of reserving her look of joy exclusively for her husband. She appreciated nature, the kindness of others, animals, and the simple pleasures of everyday life. And this disgusts the duke. It seems the duchess cared about her husband and often showed him that look of joy and love, but he feels that the duchess "ranked / [his] gift of a nine-hundred-years-old name / With anybody's gift" (lines 32 - 34). The painting captures her true joy and beauty because she reveals it to just about anyone, including the painter. That 'spot of joy' on her cheek isn't just dependent on her husband being there. Here the duke starts to elaborate on the problem: she's just too happy, and he is not the only one that makes her happy. His favours, some stupid cherries, the mule she rode around on - all of these things make her happy and make her smile and make her heart 'glad.' And the 'she thanked men' part tells us it's not just about her being happy. It's about him thinking she's being flirtatious with lots of other men.
In portraying the vivacious duchess’s character through the Duke’s projection, Browning criticizes the patriarchal and misogynist attitude of the Victorian era.
Objectively, it's easy to identify the duke as a monster, since he had his wife murdered for what comes across as fairly innocuous behaviour. Throughout the dramatic monologue the Duke reveals his pride, his vanity and his need for control. His arrogance and jealousy stem from his aristocratic ancestry and we, the audience, see him as a shallow human being unable to ever show true love to his Duchesses. And yet the ironic disconnect that colors most of Browning's monologues is particularly strong here. A remarkably amoral man nevertheless has a lovely sense of beauty and oratory skill.