A few years ago I had the pleasure of ascending in a helium balloon tethered in the Borghese gardens. From the balloon the city was laid out to our gaze, from the regular nineteenth-century blocks round the Via Nomentana in one direction to the tangled streetscape of the Campus Martius in another, a vista of rooftops punctuated by tall monuments from the city's Christian and Classical pasts. The operators of the balloon advertised it as ‘Rome's eighth hill’, a marketing tactic that relied simultaneously on the universal human fascination with looking down from high places, and on Rome's global reputation or ‘brand’ as a city of seven hills. It is that reputation, which V. cheerfully acknowledges as a cliché, that is the subject of this book. Like the balloon, the book offers a way of looking at the city that allows connections to be made across its different ages.

The fundamental facts are no doubt familiar to readers of this journal: though everyone knows Rome has seven hills, we also know that it does not. Any attempt to count them soon reaches more than seven, and even if we can agree to leave out minor spurs and ridges, the exclusion of the Janiculum and Vatican (and for that matter the Pincian) from the conventional enumeration reminds us that we are dealing with an idea associated with the very earliest identity of Rome, the Servian city, rather than with an objective orographical or even urban reality.

At the same time, the very vagueness of the seven-hills concept allowed it to be sustained by different interpretations over the centuries, as the ongoing debate (Carandini, Holland, et al.) over the meaning and composition of Varro's ‘Septimontium’ continues to show. For V., the fundamental nature of Rome's hilly topography, and the mystical resonance of the number seven for heptophiles like Varro (a subject of the third of her seven chapters), combined to create a fluid and flexible idea – ‘Rome's signature’, in V.'s formulation – that transcended any attempt to pin it down. As the city expanded beyond its old regal and republican core, effacing the old wall circuit and demanding reorganisation into new regions, the idea of the seven hills persisted. It helped Augustan poets find continuity in the rapid transformation of their city under the new principate, as we see in V.'s first and third chapters. As Rome expanded across the river, and then contracted into a medieval city looking towards the Vatican rather than the Forum, the membership of the septet could be tweaked to keep the idea alive even when the hills themselves, no longer served by aqueducts, largely ceased to be habitable.

The idea of the hills was thus ‘beyond time’, connecting together, for example, literary creations of Rome from different ages, or the mythical past with the lived present. ‘Poets pitted themselves against one another for a definitive version’, and later on Renaissance artists, papal and Napoleonic and Fascist builders all fastened on the idea as a marker of the City's quiddity, all the more potent for its flexible relationship with reality. The persuasiveness and attractiveness and long-lived replicability of this idea – what the internet age (though not V.) might call a ‘meme’ – is seen in V.'s long and entertaining lists of other world cities that have claimed a seven-hill status for themselves, as if to poach some of Rome's reputation.

The actual evidence for the importance of the seven-hills concept in ancient Roman thought, discussed in V.'s third and fourth chapters, is not particularly abundant. The idea first surfaces in the Late Republic. Cicero mentions it in a letter to Atticus, and Dionysius of Halicarnassus, Livy and most famously Varro discuss it. V. thinks that Varro was not ‘inventing the concept … [but] attempting to understand how the Romans got there’. Virgil claimed that Romulus gave Rome its seven walled hills; Ovid, Horace, Tibullus and Propertius give further testimony to the importance of the idea in the Augustan period, strengthening V.'s argument that its appeal to permanence and antiquity were particularly useful at this time of change, ‘a figure of speech which allowed Rome to remain true to itself’. Late in the first century a.d. Silius Italicus, Martial and Statius reanimated the idea as the Flavian dynasty reached for the mantle of Augustus in reimagining the shattered city; after that we have to skip forward to Claudian in another perilous moment at the end of the fourth century.

The visual arts offer little real support for the ancient period. Ancient sculptors and painters, as far as we can tell, generally shunned the challenge of reducing the seven hills, jointly or severally, into recognisable iconographic devices. V. gives us inter alia as exceptions a Flavian coin and an interesting if rather lumpy monument from Corinth, but argues that representing the hills would have risked reducing the city to the level of the captured geography depicted in paintings and tableaux in triumphs. The practical constraints of representing such a landscape before the Renaissance seem to me at least as important: the blancmange-like stemma of the Chigi popes, seen all over Rome, and the medieval representations of Rome reproduced by V., showing the hills standing in awkward isolation like chocolate truffles on a plate, show that rendering a discrete number of hills as a recognisable badge was hard to do in a convincing way, especially within the formal confines of a coin, relief or even sculptural group.

The Renaissance was when artists did begin to represent the seven hills visually. V. gives two case studies in the second half of her fifth chapter, a set of sixteenth-century frescos in the Villa Giulia and a series of nineteenth-century engravings by Rossini. For V. the Renaissance attempts to define and represent the canonical seven, rather than leave its membership in the minds of the reader, ‘atomized’ a Rome that now existed as ‘a foreign country to be mined for valuable fragments’ rather than an organic living city. These and the later visual responses to the seven hills – and V.'s engaging sixth chapter on views from the hills and the idea of the totalising (balloon-like) view from above in Roman and modern thought – take us through the Rome of the popes, the impact of the grand tour, the rise of antiquarianism and the emergence of art history as a discipline; by the time of Rossini's nineteenth-century engravings, the idea of the seven hills ‘offer[ed] a lens for looking at Rome’, one taken up in the twentieth century by Mussolini.

There are, of course, as V. acknowledges, many other possible lenses. There are endless ways of seeing and reading Rome, and different ways of approaching the hills themselves. But by taking a very old and persistent idea about Rome and charting its history over time, V. has found an ambitious way of bringing together poetic, artistic, cultural and political responses to the city that span its different ages. To do this naturally requires an interdisciplinary approach, dealing with ancient antiquarians and poets, twelfth-century pilgrims, Renaissance humanists, sixteenth- and nineteenth-century artists and more. V. handles this challenge proficiently, though her diachronic approach to such a large subject naturally involves selectivity and omission. The style is fluent and lively, though as a corollary there is sometimes a tendency to quite broadly associative writing. The volume is sure to be of great interest and use to scholars and students of Rome as a city, and the ideological importance of landscape and place in the ancient world, both for its ideas and its commendable collection of passages, images (a hundred) and bibliography.