Browning wrote “Porphyria’s Lover” in iambic tetrameter, which means that each line consists of four iambic feet. (Recall that an iamb has one unstressed syllable followed by a stressed syllable, as in “a-wake.”) Iambic tetrameter has a light-footed quality compared to the more “heroic” sound of its close cousin, iambic pentameter. This is why iambic tetrameter is often used for songs and ballads. Thus, when the poem begins, it’s easy for the reader to think that the poem will be light and—given the title—possibly even romantic. The clichéd dark and stormy night of the poem’s opening further suggests the atmosphere of gothic romance (lines 1–5):

     The rain / set ear- / ly in / to-night,
            The sull- / en wind / was soon / a-wake,
     It tore / the elm- / tops down / for spite,
            And did / its worst / to vex / the lake:
            I list- / ened with heart / fit to / break.

The first four lines of the poem feature perfectly regular iambic tetrameter. Matched with the ABAB rhyme scheme, these lines could form the beginning of a song. But intriguingly, the perfect regularity of the meter breaks down in the fifth line. Only the first foot in this line is an iamb. The second is a three-syllable foot known as an anapest (unstressed–unstressed–stressed), which is then followed by two trochees (stressed–unstressed), the second of which has dropped its final syllable. As the last line’s broken rhythm suggests, the poem might not be as light as its meter initially suggests.

Moments of metrical irregularity are especially meaningful in this poem. The meter tends to break down most noticeably when the speaker’s passion is enflamed. As an example, consider the moment Porphyria laments her inability to give herself over entirely to the speaker (lines 21–25):

     Mur-mur / -ing how / she loved / me — she
            Too weak, / for all / her heart’s / en-dea-vour,
     To set / its strugg- / ling pass- / ion free
            From pride, / and vain- / er ties / dis-sev-er,
            And give / her-self / to me / for ev-er.

The stress pattern of the opening word, “murmuring,” creates an unexpected galloping rhythm. Browning subtly echoes this galloping rhythm two lines later, with the word “struggling,” which technically contains only two syllables, but which may easily be pronounced as having three: “stru-ggl-ing.” More obvious in these lines, however, are the extra unstressed syllables that dangle off the ends of the second, fourth, and fifth lines. These small variations in the meter disrupt the otherwise placid surface of the poem’s metrical regularity, thus demonstrating disturbances in the speaker’s psychology. These disturbances always relate to his feelings for Porphyria. As such, it’s also significant to note that Porphyria’s very name cannot be contained within the poem’s iambic rhythm: “Por-phy-ri-a.” The appearance of her name thus always marks a subtle disruption, as happens when she first enters the poem in line 6: “When gli- / ded in / Por-phy- / r-ia; straight.”