Adonais begins with an epigraph of Greek elegiac poetry attributed to Plato. The epigraph is followed by Percy Bysshe Shelley’s preface to the poem proper, which quotes Greek lines from the “Lament for Bion,” an ancient poem, possibly by Moschus, on the death of the second century b.c.e. poet who composed a “Lament for Adonis.” Later, following a reference to John Keats’s death in Rome early in 1821 and his burial there in the Protestant Cemetery, Shelley claims that Keats’s pulmonary tuberculosis derived from the harsh, anonymous attack on Keats’s long poem Endymion: A Poetic Romance (1818) in the Quarterly Review. Denouncing the reviewers, Shelley asks how they could favorably treat works by bad writers but act so hostile to Endymion, which, regardless of its flaws, deserved far better treatment. As Shelley nears the end of his preface, he again says, in effect, that critical animosity killed Keats. Upon concluding this direct, literal response to the poet’s death, he launches into his elegy proper, which is set in mythic time and space.

Through the first two-thirds of its fifty-five stanzas, Adonais is a pastoral elegy, revealing the influence of the ancient Greek-speaking poets Bion and (presumably) Moschus, as well as that of Shelley’s English predecessors Edmund Spenser, who wrote Astrophel (1595), and John Milton, who wrote “Lycidas” (1638). The pastoral tradition appears when Shelley invokes a Muse (one of a set of nine Greek goddesses), presents poets as shepherds, and depicts mourners in procession. Writing in an overtly artificial tradition, Shelley displays genuine emotion and daringly places himself in a line of illustrious forerunners.

The verse form of Adonais, the Spenserian stanza, mimics a form created by Spenser that comprises eight lines of iambic pentameter and a ninth line of iambic hexameter (an Alexandrine). Each of the first eight lines of a stanza is built with five metric feet, and each of those feet, with occasional exceptions, consists of a relatively unstressed syllable followed by a relatively stressed one. The ninth line of each stanza has an extra metric foot and thus tends to make a reader pay special attention. In conventional notation, with letters representing rhyming sounds, the tightly binding rhyme scheme of a Spenserian stanza is ababbcbcc.

Shelley and Keats had met and talked several times in England but had never become close friends. Keats wanted to keep a distance from Shelley, who was better known than Keats as a poet and came from a higher social class. While living in Italy, Shelley heard in July, 1820, that Keats was ill and invited him to come to Italy. Shelley’s letter contained gentle criticism of Endymion, and Keats, in his grateful reply to the invitation, responded with polite criticism of Shelley’s poetry. Eventually, Keats sailed to Italy, but he never reached Pisa, where Shelley was then living. Instead, Keats died in Rome on February 23, 1821, and was buried in the Protestant Cemetery, near the grave of Shelley’s son William.

Shelley started writing Adonais soon after he learned on April 11 of Keats’s death, and the first copies, from a Pisan printer, appeared on July 12. The copies that Shelley sent to his English publisher sold poorly, and the elegy received two disparaging reviews late in 1821. Most of the critical response since then, however, has been admiring, as was Shelley’s own opinion of the work.

With a title conflating Adonis, Aphrodite’s slain lover, with Adonai, a Hebrew word translated as “Lord,” Adonais is as much about Shelley as about Keats. The anonymous evaluation of Endymion in the Quarterly Review , while unpleasant...