The creator of the titular work worked busily a day to produce the "depth and passion of its earnest glance," though it is now located behind a curtain that only the speaker of the poem puts by.  
Richard Howard wrote a response to this literary work in the form of a poem spoken by Nikolaus Mardruz to his master, Count Ferdinand.  The title character of this work rode a white mule round the terrace, and was known to be fond of a bough of cherries, even if they were broken for her by "some officious fool."  The creator of the titular work worked busily a day to produce the "depth and passion of its earnest glance," though it is now located behind a curtain that only the speaker of the poem puts by.  The last lines of the poem mention a bronze statue of Neptune taming a sea-horse, which was cast by Claus of Innsbruck, though the titular work was painted by Fra Pandolf.  FTP, name this poem written in 1842, a dramatic monologue spoken by the duke of Ferrara and written by Robert Browning.
Richard Howard wrote a response to this literary work in the form of a poem spoken by Nikolaus Mardruz to his master, Count Ferdinand.  
"My Last Duchess"