Thursday, September 28, 2017


Richard J. A. Talbert, Roman Portable Sundials: The Empire in your Hand. Oxford; New York: Oxford University Press, 2017. Pp. xxiii, 236. ISBN 9780190273484. $55.00.

Reviewed by Andrew M. Riggsby, University of Texas at Austin (

Version at BMCR home site


The force of this book's title may not be clear on first reading. On the one hand, Talbert is not talking even about all Roman portable sundials, but only those (a majority) which have geographical information inscribed on them.1 At the heart of the book is a catalog (nearly half the main text) of the sixteen such devices currently known. On the other, Talbert does not limit himself to the history of time-keeping. He originally came to these devices as evidence for ancient geographical world-views (hence the subtitle), and there are chapters on that question among others. I will begin with a summary of the more or less factual contents (treating the reference elements of the book before the more analytic chapters), then discuss some broader implications.

Those "reference elements" consist of the catalog (chapter 2) and a set of maps, lists, and tables (203-219). Each catalog entry is identified by a name (typically referring to location in which it is held), a three-letter abbreviation of that name, and a serial numeration. This is followed by current location (three or four are now lost), material, dimensions, provenance, description, date, and bibliography. Each is well illustrated by photographs (where possible) and line drawings, while maps and tables record the inscribed geographical information. The "description" sections also attempt to identify problematic locations and latitude values mentioned on the dials (this continues in ch.4). This is not trivial because of damage to the objects, heavy abbreviation of names, the variable reliability of ancient geographical knowledge, and ambiguity between homonymous sites. Use was made of Reflectance Transformation Imaging (RTI) to arrive at new readings on several of the dials. Individual devices sometimes raise unique questions, such as the order of apparently successive additions of names to OXFORD, and the mechanism of operation of VIENNA and BALKANS. (In the main text, Talbert often uses just the name of the city, with ALL CAPS, for a device whose "proper" name in his catalog is that of a museum.)

The sixteen dials were found across most of the Empire (p. 138). Five include references to Constantinople. Four have termini post quem between 80 and 180 CE, but could be much later than that. Differences between the eight Latin and eight Greek examples are modest.

At the end of the book a gazetteer, set of maps, and table of latitudes and locations summarize all the geographical information from the various dials in composite form. The reader should note (23-4) that these composite maps follow different representational conventions than those in the individual catalog entries.

Chapter 1 briefly introduces the use of sundials in the Roman world, with focus on three methods of operation of portable models.2 The types cataloged here had to be adjusted for latitude and time of year before use. In far the most common type, this was done by rotating a series of parts, then suspending the whole and observing where a shadow fell on the face. The need to know the latitude gives rise to the inscribed lists of data.

Chapter 3 investigates the "geographical awareness and worldviews" of the users of these dials. The dials list two kind of information. The first (which defines Talbert's corpus) is place names, mostly of cities and provinces (never natural features). The other (found on most of them) is figures for latitude. Between abbreviation and homonymy most dials have significantly ambiguous information, especially for a user who did not participate in the original design. Accuracy of latitudes (whether compared to reality or to the Ptolemaic state of the art) varies considerably both within and across dials, and this is aggravated in cases of provinces/regions, which are always given a single latitude. The order of places in the lists often follows that of their latitudes, but seems sometimes to be inflected by grouping of adjacent regions. Two seem to be ordered as circuit tours. Most span the bulk of the empire, albeit unevenly. In a technical sense, use of these sundials does not require any very specific worldview, and Talbert reasonably identifies this as a valuable feature. What the dials suggest, however, is more specific. First, they confirm Talbert's own earlier intuition that provinces and their rough positions made up an important Roman framework for geographical understanding. Second, the importance of latitude to most of these devices suggests a broad internalization of a Ptolemaic, two-dimensional view of space, even if not directly from Ptolemy nor by way of formal cartography. Chapter 4 turns to the persons who used and produced portable sundials. There is little external evidence, whether in literary texts or in the (largely unknown) archeological contexts of the dials.3 Nor does any dial record its own maker or owner; everything must be inferred from the operation of the device. The geographical errors noted above and the difficulty of calibrating these quite small devices would have interfered with accurate time-keeping. Such a rough-and-ready approach contrasts with the precision seemingly promised by the several dials which list some latitudes to the fraction of a degree. At the same time, at least some geographical howlers would have translated into modest-seeming errors of time (p. 143). The lists of names generally show some degree of personalization by combining a selection of broadly scattered "greatest hits" with lesser and/or tightly clustered locations. Talbert closes with the reasonable suggestion that the network of designers, makers, and users merits the term "community," given the shared general knowledge that almost all must have had and traces of some quite specific traditions that seem to underlie some of the individual dials.

Chapter 5 briefly treats post-classical comparanda, running from early Islamic astrolabes to modern luxury watches. These are treated, I think rightly, as parallels to the Roman dials, rather than as instances of their reception.

An appendix concludes the analysis, considering an epigraphic fragment from Aquincum (in modern Hungary, on the outskirts of Budapest). Talbert argues convincingly that it is a "manual"—I might have said "set of templates"—for sundial makers, though not necessarily used for portable models.

These objects have all been published before, and most of them even collected in highly schematic lists, but they have not been genuinely accessible as a set.4 As a result, we have also lacked basic groundwork that Talbert provides on, for instance, the real and imagined locations of places, the ways they are arranged in the inscriptions, and even the basic text and translation of those inscriptions. In fact, it is useful to think of this book as the historical counterpart of what in literary studies would be the first major scholarly edition and commentary on a recently discovered text. Talbert writes (p. xiii): "My hope is that the book will both enlighten and intrigue readers across disciplines by uncovering a fresh, imaginative vision of the world shared by what might be termed a loose community of Romans." Mission accomplished.

With that in mind, let me take the liberty of suggesting what I think would be a very productive next step, starting from very technical time-keeping issues, but feeding eventually into much broader questions. One the one hand, we can calculate how much ancient measurements would have varied both from the notional norm and from each other.5 On the other, we can locate specific contexts in which Romans did or might have used sundials. Talbert and others have already shown that Roman tolerance for error/variation must have been greater than today's, but with more concrete descriptions of that variation in hand, we can think more specifically about how it would play out in different use contexts. Could you schedule in advance a meeting with someone you had never met? Even someone you know well? Use a sundial to measure the duration of a march or roast? Be confident you had completed duties within a legally imposed time limit (p. 164)? Talbert has a good survey of contexts in which norms of time were imposed generically (pp. 163-7).6 To this we should add at least the evidence collected by Ray Laurence on cases of times imposed by agreement or simply noted.7 Knowing how well the portable sundials could perform these tasks would then in turn be relevant to two kinds of big question. One is the conceptualization of measurement. What did a Roman who said something weighed two pounds or was to happen at the fourth hour think she was claiming? The other is more social. Talbert notes the likely value of these as prestige objects accessible to the merely well-to-do, as symbols of national pride, as souvenirs, and as both bearers and symbols of cultural capital. Having a more granular sense of their practical value would help us sort out how and why portable sundials were used in various contexts.

Finally, I would note Talbert's view that there is likely a good deal left to be discovered. He points out how much of our evidence (even whole types of it) has only appeared in the last few decades. The existence of several arbitrary but well-observed conventions (168) shows that there was a single (or at least dominant) culture of sundial making rather than independent rediscovery of the basic principle. But the fact that within our modest current evidence for this culture there is also a great deal of internal variation (see n. 3) argues that it was a robust and diverse culture.


1.   Talbert does not enumerate non-geographical portable sundials, but I count perhaps eight known instances in the secondary literature, plus another half-dozen or so described as "miniature." As Talbert further points out, we have only one apparent literary reference to portable sundials (Vitruvius, De arch. 9.8.1), but it seems very matter-of-fact.
2.   PHILIPPI operates on one of these principles, but its design is so different from its kin that it could have made for a fourth type. BALKANS is also distinctive in design. Moreover, we could distinguish the "normal" use of an hourglass layout of lines on the face from the set of curves on MÉRIDA and VIGNACOURT. Finally, MEMPHIS and SAMOS exhibit as-yet unexplained secondary networks.
3.   A couple of mosaics show figures holding sundials, but these seem to be much larger than any of the surviving portable types. See M. Olszewski (2015). "Les cadrans solaires dans les mosaïques romaines et byzantines (Ier siècle ap. J.-C. – IXe siècle ap. J.-C)." Pp. 449-68 in A. Tomas (ed.) Ad Fines Imperii Romani for images.
4.   M. Arnaldi and K. Schaldach (1997). "A Roman Cylinder Dial: Witness to a Forgotten Tradition." Journal for the History of Astronomy, 28, 108; E. Winter (2013). Zeitzeichen: Zur Entwicklung und Verwendung antiker Zeitmesser. Berlin: De Gruyter. Pp. 78-9; J. Bonnin (2015). La mesure du temps dans l'Antiquité. Paris: Belles Lettres. Pp. 387-401.
5.   Calculations for two particular cases in: Arnaldi and Schaldach 1997.112-4 and D. Savoie (2007). "Le cadran solaire grec d'Aï Khanoum : la question de l'exactitude des cadrans antiques." Comptes rendus des séances de l'Académie des Inscriptions et Belles-Lettres, 151, 1161-1190. More general discussion at Bonnin 2015.167-70, but still without reference to individual use contexts.
6.   Esp. S. Remijsen (2007). "The Postal Service and the Hour as a Unit of Time in Antiquity." Historia, 56, 127- 140.
7.   R. Laurence (2007). Roman Pompeii: Space and Society2. New York: Routledge. Pp. 154-66. The second edition is crucial on this point.

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