Porphyria's lover then talks of the corpse's blue eyes, golden hair, and describes the feelings of perfect happiness the murder gives him and his surprise at God's subsequent silence.
A possible source for the poem is John Wilson's "Extracts from Gosschen's Diary", a lurid account of a murder published in Blackwood's Magazine in 1818.
Browning's friend and fellow poet Bryan Procter acknowledged basing his 1820 "Marcian Colonna" on this source, but added a new detail; after the murder, the killer sits up all night with his victim.
Each monologue offers the speaker's reasons for the desired woman from subject to object: in "My Last Duchess", the Duke may have jealously murdered his wife, but keeps a portrait of her behind a curtain so none can look upon her smile without his permission; in "Porphyria's Lover", the persona wishes to stop time at a single perfect moment and so kills his lover and sits all night embracing her carefully arranged body.
Her "rosy little head" may also be a sly reference to the hymen; Porphyria leaves a "gay feast" and comes in from the outside world wearing "soiled gloves"; now her blue eyes, open in death, are "without a stain".
At the poem's midpoint, the persona suddenly takes action, strangling Porphyria, propping her body against his, and boasting that afterward, her head lay on his shoulder.
Porphyria, which usually involved delusional madness and death, was classified several years before the poem's publication; Browning, who had an avid interest in such pathologies, may well have been aware of the new disease, and used it in this way to express his knowledge.
This is indicative of the allegorical content of "Porphyria's Lover" in which both characters imitate the process of artistic creation: when art is created or published, it is dead and forever unchanging.
Tennyson shares similar ideas in "The Lady of Shalott", as do other Victorian authors who contribute to the popular conversation about the artistic processes.