Frontier landscapes constitute complex realities, primarily when characterised by a conspicuous military presence. Indeed, their development depends on many factors and dynamics: the morphology of the territory, the position and strength of the enemy, the need to control movement, the possibility of communication and the rapid movement of armies. Using 1st-century-AD — especially Flavian — Scotland as a case study, Andrew Tibbs uses archaeological and historical legacy data and spatial analysis techniques to attempt to piece together the complex dynamics of such a landscape.
In recent years, the development of digital analysis tools has profoundly changed the archaeological study of landscapes. Andrew Tibbs’ work fits into the framework of these studies, with an analysis that is attentive to detail and aware of its means and limits, and which pays particular attention to the relationship between the anthropic element and the natural landscape. While these aspects place Tibbs’ work in line with the most recent research, the absolute novelty of this study is the use of GIS and spatial analysis applied to this case study. The study of a frontier landscape is always complex. The Scottish case is perhaps among the toughest due to the unreliability of archaeological data, lack of knowledge of the palaeo-environments and, in part, due to the biases produced by the only literary source describing the Roman presence in the area: Tacitus’ Agricola.
In the first chapter, the author immediately clarifies what gap this work intends to fill: the need for GIS-based studies on this territory, which consider Roman fortifications within a broader environmental, landscape and strategic framework and not only from an architectonical or typological point of view. The objectives of the study are clear and well stated: to understand the military strategies that led to the selection of areas to be fortified, to assess to what extent the network of fortifications was able to control the territory through surveillance and visual communication, and to verify the interconnectivity between sites based on the network of roads and rivers. Correctly, the author points out the limitations of the research and the biases that the use of legacy data produces, especially regarding site dating, knowledge of landscape features, heterogeneity, and varying degrees of data reliability. Moreover, as the author points out, studies of many of Scotland’s Roman sites are unpublished, and the original data are often incomplete or inaccessible.
The second chapter provides an overview of the study area from both an archaeological and historiographical perspective, with a constant and helpful dialogue with literary sources. Scotland represents a multi-layered and dynamic frontier area, with phases that may extend to a pre-Agricola period, as some archaeological evidence and previous studies would indicate. In the chapter, the different types of fortifications known in Scotland are made clear, and, at the same time, the complexity of reading this landscape is highlighted: other nebulous types of settlements indeed exist, which may also have had a military function. By describing in sufficient detail the types and functions of the various forms of fortification, the chapter provides even a reader not specialised in the subject with the necessary tools for understanding the approach and the study’s importance.
Difficulties in this kind of analysis are evident, and a careless approach to the study would have led to oversimplified results. The author is aware of this and, in the third chapter, exposes the unreliability of much of the data, the uncertainties in interpretation, and the biases produced by heterogeneous research methods. In addition, he stresses the need for reliable paleo-environmental data defining the characteristics of the environment and landscape of the time.
The next section of the book is related to the spatial analysis of data on QGIS. It is divided into chapters that examine four components that may have influenced developments in the network of fortifications: location and positioning, intervisibility among fortifications, orientation, and interconnectivity.
In a dialogue between literary sources (‘Pseudo’ Hyginus and Vegetius) and spatial analyses, in the fourth chapter, Tibbs points out how the positioning criteria illustrated by ancient authors are not necessarily considered in the Scottish case, which presents peculiarities connected to morphology and topography, the need to control the river and road network, and the organisation of indigenous fortifications. In this chapter, the images are particularly effective, showing the results of the viewshed analyses and illustrating the control possibilities of the different fortifications.
The viewshed analyses focus on the possibility and importance of communication via fire beacon chains and how decisive this was in positioning the fortifications. To evaluate and possibly confirm hypotheses already proposed by other authors, Tibbs consciously forces the analyses, validating them even when he uses excessive distances or by increasing the height of some observation points. An example of that is the case of camps where he assumes the presence of towers, although they are not known archaeologically. The results of the analyses, on the one hand, confirm the possible existence of fire beacon chains between buildings, camps, and forts and highlight areas for future field analyses to identify other fortifications; on the other hand, as the author himself emphasises, the need to communicate using signals does not seem to have been a factor of primary importance for the positioning of many of the sites. Unfortunately, the graphic apparatus of the chapter could be more effective.
The distance between literary sources and archaeological data also emerges from analysing the orientation of fortifications. According to the sources, the orientation of a fortification was deliberately chosen: it must face east, the enemy or the direction of advancement. However, in the Scottish case, this criterion is not met. Instead, going along with landscape morphology, the need for control over the landscape determines the orientation of fortifications. For example, Crawford Fort is positioned at the junction of two valleys and toward a waterway, while the Cumbrian forts are all oriented toward the west or northwest controlling the coast.
The closing part of the analysis section presents a study of the interconnectivity between fortifications. Unfortunately, the limited knowledge of the period’s road network makes the results decidedly partial. However, one interesting result is the discovery of the importance of coastal control and the river network. Valuable insights are offered here to re-evaluate the role of waterways in controlling territory, movements and, probably, communication between the network of fortifications.
Finally, a discussion chapter highlights and summarises the main findings. Of particular interest is the analysis of the fortifications located along the coast, often at the mouths of rivers, where supplies for the troops could land. The study demonstrates that the placement of forts, fortresses and encampments reflects the need to control valleys and communication routes both on land and water, rather than the need to control the entire territory.
Tibbs’ study offers new insights into the structure and characteristics of frontier landscapes, not only those in Scotland. The conscious use of the possibilities provided by GIS, of legacy data with their limits of reliability and their potential, and the constant comparison with literary sources are some of the elements that make this study interesting and rich in insights.
Each chapter has a clear structure, with an introductory paragraph highlighting research questions and issues, a central analytical part, and a summary highlighting the results. This structure facilitates reading and makes the analytical process clear. For each chapter, a background on the topic is provided so that the starting point is clear, as well as the importance of the outcomes. The graphical apparatus is well managed, and most images are functional for understanding the text and the results. However, it is unclear why the author preferred not to use hillshade as a background for some figures. This would have been a more effective solution than contour lines, especially for the intervisibility analyses.
The study is well structured, and the analyses are effective. However, despite the tables in the appendix, the work could have been enriched by a more accurate description of the dataset and its structure. For instance, it is necessary to read some passages several times to understand how many sites compose the dataset; a description of the attribute tables is missing. This makes some aspects unclear: how were the collected data standardised? Do the analyses consider the reliability of the data? Are the data structured to be easy to query? More importantly, are the datasets produced during the study published? Is this study replicable? Spatial analyses are effective and help to understand the dynamics of the landscape. The quantity and ubiquity of the data should have allowed for more complex geostatistical analyses (e.g. Point Pattern Analysis) that would have added additional elements to understand the fortification-environment relationship.
In conclusion, this study is a conscious dialogue between literary sources, structural types of fortification, tactical considerations, and the application of spatial analysis in a GIS environment. In this way, the author sketches with verisimilitude the ancient frontier landscape: a dynamic, dense and now, thanks to the author, less nebulous landscape.