Browning used the dramatic monologue in his poems. My last duchess is one example. Refer by way of example to this poem,
and in particular to lines THIS GREW; I GAVE COMMANDS until the last line CAST IN BRONZE FOR ME!
Dramatic monologues often reveal a great deal about the speaker, and often refer to actions, either obliquely or directly. Another poem you might refer to for comparison is Browning's 'Porphyria's Lover', in which the speaker graphically confesses to murder.
In this case, the Duke, entertaining a guest at his court, begins reminiscing about the portrait sessions, then about the Duchess herself. His musings give way to a bitter diatribe: she displeased him, she flirted with everyone, treated her husband's attentions in the same way she might receive anyone's. Crucially, she appeared to rank his 'gift of a nine-hundred-years-old name' as no more special than the gift of any other man at court. The Duchess had offended his pride - he could have berated her for her behaviour - he uses the word 'disgust' - but could not bring himself to: 'I choose never to stoop.'
Note how the tone barely changes with 'this grew; I gave commands, then all smiles stopped together.' This revelation ought to be 'dramatic', but is delivered with a chilling matter-of-factness. It might take two or three readings before we realise that the 'commands' were orders for the Duchess to be killed. (I recommend you should always read a dramatic monologue out loud - test the tone for yourself.)
Having made this disclosure, the Duke returns to the business at hand: the guest is an emissary, arranging the Duke's next marriage, with another young girl. As the Duke and the emissary turn to join the rest of the company, the Duke points out another notable artwork, this time a sculpture of Neptune 'taming a sea-horse'. The lasting image is of control, an active 'taming', juxtaposed with being 'cast in bronze', and we are reminded of the portrait 'as if she were alive'.