In "My Last Duchess," how did the duke respond to the duchess’s behavior at first?
At first, it seems that the duke responded to the duchess's behavior by taking note of everything that seemed to make her happy: a cherry tree branch, a white mule, a sunset, the duke himself. The modesty or value of the gift made no difference to her; there was no distinction in the joy she felt, whether the gift was large or small, valuable or cheap. Finally, the duke became offended that "she ranked / [His] gift of a nine-hundred-years-old name / With anybody’s gift." In other words, she cherished his gifts, including the gifts of his status and wealth, only as much as she appreciated any other, smaller, gift, and this upset him. He says,
Even had you skillIn speech—which I have not—to make your willQuite clear to such an one, and say, "Just thisOr that in you disgusts me; here you miss,Or there exceed the mark"— and if she letHerself be lessoned so, nor plainly setHer wits to yours, forsooth, and made excuse—E’en then would be some stooping; and I chooseNever to stoop.