Terza rima, the form that Robert Bridges employs in "London Snow," is a complex one known for conveying unity and interconnection. In its most traditional form, it splits a poem into discrete but related tercets, in which the first and third lines of the tercet rhyme with one another. The unrhymed second line, meanwhile, sets the rhyme for the first and third lines of the following stanza. Therefore, the poem's rhyme scheme tends to look something like aba bcb cdc ded. Terza rima lines are also often written in iambic pentameter, though it is the form's rhyme scheme that makes it truly distinct. Originally Italian, terza rima is perhaps best-known for its use in Dante Alighieri's Divine Comedy. Since that usage, it has appeared in both Italian and non-Italian poetry—and translators have wrestled with the dilemmas it creates for them.
Dante invented the Terza Rima for use in his best-known work—and indeed, one of the best-known works of poetry ever written—The Divine Comedy. Over the course of three books, Inferno, Purgatorio, and Paradiso, a fictionalized version of the author traverses nine circles of hell and makes his way through purgatory before arriving in heaven. In a book laden with Catholic thematic content, Dante's form also continuously refers to various aspects of Christian belief. For instance, each of the three books of the Divine Comedy is composed of thirty-three cantos, or sections (though the Inferno does contain an additional introductory canto). Thirty-three is a number of particular significance for Christians, since in Christian tradition it is the age at which Jesus died. Moreover, the tercets (or three-line stanzas) used in terza rima may, in the case of the Divine Comedy, reference the Trinity of the father, the son, and the holy spirit. Its interlocking rhyme scheme, in this reading, emphasizes the connections between each aspect of the Trinity.
Italian poets like Petrarch, inspired by Dante's use of terza rima, explored the form themselves—but it made its way to English via Geoffrey Chaucer, who used it in the poem "Complaints to His Lady." It achieved unprecedented popularity in English with the Romantic poets, especially Percy Bysshe Shelley. His "Ode to the West Wind" includes four tercets and a couplet written in terza rima iambic pentameter. The final line of the poem's concluding couplet rhymes with the middle line of its preceding tercet. In his poem, the terza rima's lively back-and-forth action, connecting one stanza to another, imitates and evokes the movement of the wind. Lord Byron, a contemporary of Shelley's, also made use of terza rima. Perhaps not coincidentally, these two poets spent a great deal of time in Italy and were particularly inspired by Italian culture, ruins, and even politics. Thus, their use of terza rima may also be tied to their interest in Italy more generally.
While English-language poets from Derek Walcott to T.S. Eliot to William Carlos Williams have periodically used terza rima, some of its most intriguing English usage has come in the form of translations from Italian. This is particularly true for translations of the Divine Comedy, one of the most translated books in the world. Translators of Dante face a steep challenge: whereas rhymes are plentiful and natural-sounding in Italian, English offers fewer rhymes, at times causing rhyming translations to sound forced and awkward. Some translators, such as John Ciardi, have chosen not to focus on maintaining the terza rima form, concluding that its strictures would inevitably compromise the rendering of other aspects. But the poet Robert Pinsky, in a 1996 translation, chose to maintain Dante's original rhyme scheme while employing a great deal of slant rhyme and near rhyme. The scholar Rachel Jacoff noted that Pinsky's translation, with its flexible use of rhyme, avoided the "archaism nor the awkward padding characteristic of many verse translations, which fill out lines for purposes of rhyme."
Robert Bridges' use of terza rima in "London Snow" may be intended to reflect the endlessness and seamlessness of the snow—after all, the form is theoretically endless, extending until the poet chooses to conclude. It also may emphasize the interconnectedness of the natural world with its interlocking stanzas. Finally, Bridges' poem contains a number of religious allusions, and he, like Dante, may be employing the form in reference to Christian tradition. As an English-language poet somewhat hampered by the difficulty of rhyming in English, Bridges makes his chosen form work through two adjustments: he occasionally uses slant rhyme, and he dispenses with the traditional iambic pentameter meter of terza rima. These modifications from tradition are themselves part of a tradition—that of English-language terza rima, in both original and translated poetry.
