In posing questions about what is “historical” and what counts as “poetics,” historical poetics cannot separate the practice of reading a poem from the histories and theories of reading that mediate our ideas about poetry. While nineteenth-century verse cultures revolved around reading by generic recognition, a reading of poetry as a form of cognition emerges among later critics like I. A. Richards, who illustrates how a line from Robert Browning is read in the mind’s eye, as if in the present tense. But Browning was already doing a version of historical poetics, in writing “Pan and Luna” as a poem about reading other poems about Pan, among them “A Musical Instrument,” by Elizabeth Barrett Browning. In the composition and reception of her poem, we see how Victorian poetry foregrounds its multiple mediations, including the mediation of voice by meter as a musical instrument. The recirculation of her popular poem through citation and recitation, illustration and anthologization, prosody and parody, demonstrates a varied history of thinking through—simultaneously “about” and “in”—verse.