For twenty years now, the single star on the spine of Filippo Coarelli's 1997 masterpiece, Il Campo Marzio. Dalle origini alla fine della Repubblica, has tantalized students of ancient Rome's topography and urban history with the prospect of a second volume on the Campus Martius, covering (like his second volume on the Roman Forum, with its double-starred spine) the imperial period. But a second volume has not materialized, which has left us without monographic coverage of this key area of the city during the whole sweep of its development in antiquity. Recent scholarship, much of it excellent, has focused instead on specific monuments, specific periods, or specific sectors within the Field of Mars. The only holistic study of the ancient Campus Martius has been T. P. Wiseman's superb, but necessarily brief, entry in the Lexicon Topographicum Urbis Romae (vol. 1, 1993). Given the distinctive character of this part of the city, its functional significance within the wider urban context of ancient Rome and the dramatic changes over the long term in its physical topography and urban fabric, the absence of a comprehensive, up-to-date overview of the Campus Martius has been ever more conspicuous. Much of that lacuna has now been filled by the two very different but complementary books under review.

Paul Jacobs' Campus Martius, completed with the assistance of Diane Conlin, is the work of a non-specialist devotee of this endlessly fascinating urban quarter. A lawyer by training, J. writes with zip and zeal, a sharp eye for the engaging anecdote and a knack for the arresting mise en scène (the reconstruction of what the poet Calpurnius' Corydon would have seen from the uppermost row of Nero's wooden amphitheatre, 64–6, is particularly effective). Following an introductory chapter that sets out temporal and spatial parameters, the book is organized thematically, with chapters on military matters (ch. 2), temples (ch. 3), entertainment (ch. 4), porticoes (ch. 5), water (ch. 6) and imperial building programmes (ch. 7). Much of the discussion is addressed to urban sociability and ‘daily life’ in the Campus Martius. So, for example, the chapter on entertainment includes elementary excursus on chariot racing (66–7), Roman drama (69–72) and gladiatorial combat (86–7), while that on water introduces the reader, along the way, to Roman baths and bathing culture (126–8). On occasion the treatment of these different themes can descend into a series of descriptive summaries in the style of a topographic dictionary (for example, on porticoes, 97–109, or imperial monuments, 139–61), but for the most part J.'s account moves swiftly. And there are several observations here that will be of interest to scholars. J. usefully draws attention, for example, to the dramatic ‘verticality’ of the Theatres of Pompey, Marcellus and Balbus, and to how these structures created a new ‘skyline’ within this once flat part of the city (85). He also reminds us that the notional connection between the flood plain and the god Mars was sometimes tenuous — the designation ‘Martius’ becoming attached to campus (or pedion) only, it seems, in the mid-first century b.c. (and even from that time not very common) — and suggests that it was only after the proliferation of non-martial buildings in the campus that the association with Mars became ideologically exigent, reflecting ‘an inverse relationship between the use of the area for war footing and its mythological ties to the war god and the glorification of military engagement’ (41–2). There are several similarly insightful remarks throughout the book. Its main value, though, is that it offers a reliable and neatly packaged presentation of mostly well-known information about the Campus Martius and its physical structures, supplemented by clear plans and effective illustrations. As such, it can be recommended to students and non-specialists as a good introduction to this vital region of the ancient city.

Jon Albers' Campus Martius, by contrast, is clearly aimed at a professional readership. It combines original analysis with high-level synthesis, and in fact can be read in two ways. The first is as a comprehensive and authoritative review of the urban and monumental development of the Campus Martius from its earliest recorded history through the middle imperial period. The second is as a trenchant examination of the multiple ‘axis- and grid-systems’ (Achsen- und Rastersysteme) that structured the siting and orientation of buildings and complexes within the Campus Martius, and the shifting ideologies through which the monuments of the area were invested with meaning.

As a synthesis of existing scholarship on the buildings and public spaces of the Campus Martius, A.'s book sets a new standard. Indeed, it is no exaggeration to say that subsequent work on this part of the ancient city, at least for the foreseeable future, will have to start here. Four chapters, arranged chronologically, form the empirical core of the book (chs 2–5). A. mostly adheres to consensus views on long-standing topographical puzzles. He locates the Tarentum and Trigarium complex, for example, in the extreme west end of the Campus, near the Tiber bend (47–9), and the amphitheatre of Statilius Taurus in the western part of the Circus Flaminius (104–5). But he is more cautious when it comes to the labelling of unidentified structures, such as the temples of the so-called Area Sacra di Largo Argentina or the nearby temple of the Via delle Botteghe Oscure, for all of which A. resists the temptation to assign a specific identification. A.'s own interventions are always sensible and persuasive. He is especially good on the urban impact of the Saepta in both its Republican and post-Caesarian phases (especially 50–1, 92–4, 121–2, 130–1, 191–3); on the changing sepulchral topography of the Campus Martius (84–7, 110–12, 206–9); and on the significance of the plain's location extra pomerium, which explains not only the military character of the Campus, but also the recurrent importation into it of alien cults and architectural styles from the Greek East, so crucial in the monumentalization of this part of the city, especially in and around the Circus Flaminius (52–83, 194–200). Specialists will, of course, quibble about this or that topographical detail, but no one can complain about A.'s presentation of the material. The hundreds of maps and plans, beautifully presented in this large format book, are uniformly excellent, almost always drawn with a scale and north arrow, and with hypothetical reconstructions clearly marked. An extensive catalogue at the end of the book (223–82), which also serves as an index, functions as a topographical dictionary for the structures and spaces of the Campus Martius. There are many little gems of concise scholarship here (for example, on the Basilica of Neptune, Hadrianeum, Iseum et Serapeum, Temple of Juno Curitis, the Agrippan Pantheon, Porticus Minucia, Theatre of Balbus, Via Flaminia etc.). Given the high rate of publication in the last fifteen years, most entries supersede those appearing in the Lexicon Topographicum Urbis Romae (6 vols, 1993–2000).

Even if the book were just a topographical synthesis, it would still be a worthwhile addition to the literature — and an effective rejoinder to those who argue for digital publication as the only way forward. But the empirical information so expertly presented here is also mobilized in support of a sophisticated urbanistic analysis. The various threads of A.'s larger argument are woven throughout the book, but they all come together in a short but incisive concluding chapter on ‘urban structures’ (ch. 6, 189–211). According to A., the urban development of the Campus Martius was structured, first, by its physical topography (especially its relatively flat surface, flood zones and waterways) and, second, by Republican legal norms. It is within the context of these constraints that A. situates the three principal ‘grid-systems’ that he reconstructs within the Campus Martius (mapped in fig. 109, p. 189). The first, a ‘natural’ grid, was shaped by the Tiber river, which determined the orientation of the Tarentum and Trigarium complex and the borders (such as they were) of the Circus Flaminius. The second, ‘sacred-legal’ in character, responded to the cardinal points. It was established by the early temples to Apollo Medicus and Bellona, and was then fixed by the Republican Saepta. The third and final ‘grid-system’ was a ‘pragmatic’ one, generated by the course of the Via Flaminia and articulated by the imperial monuments of the northern Campus Martius, especially the Ara Pacis and the Antonine columns and ustrina. In addition to the Via Flaminia, other roads, especially the Via Recta and what is here identified (with Coarelli) as the Via Triumphalis, helped to demarcate these grids. Even more important was the emergence of what A. calls ‘axis-systems’ (fig. 110, p. 191), defined by porticoes, uniform façades and the spread of ‘arcade-architecture’. Key examples include the porticoes fronting the Circus Flaminius; the north–south axis created by the line running from the Stadium of Domitian to the Odeum of Domitian and Pompey's Theatre; and the east–west axis separating the central from the northern Campus Martius, initially delineated by the Aqua Virgo, Saepta Julia, Pantheon, and Stagnum of Agrippa and later by the Hadrianeum, the Temple of Matidia, the Baths of Nero and the Stadium of Domitian.

In the analysis of these grids and axes, A. has little recourse to explicit theorization. Readers should not expect direct engagement with the ideas of urban theorists such as Henri Lefebvre, Kevin Lynch or Edward Soja (to name just a few). There is also less analysis than one might expect of movement through these spaces and grids. Discussion of the triumphal route, for example, is quite brief (202–5), and mostly follows the sequence proposed by E. Künzl (Der römische Triumph (1988), 30–44). What A. does stress, to very good effect, is the long-term continuity of the Campus Martius as an enormous canvas for élite representation in the public sphere. Despite the substantial changes over time in the built environment and urban functions of this part of the city, that is, it was the unremitting drive of Roman élites to memorialize themselves, both under the Republic and the Principate, that gave the ancient Campus Martius a certain coherence and, ultimately, drove the monumentalization of this flood plain. A.'s book documents this complex process systematically, and with its vivid maps and plans, allows us to visualize it more clearly than ever before.