Die Brücke über die Majrada in Chimtou

This book explores in detail the Roman-period bridge over the Medjerda (ancient Bagrada) River at Chemtou (Simitthus), Tunisia, and the extraordinary milling installation that was constructed within its collapsed sections. It makes sense of the bridge’s extremely complex stages of construction and repair, from its foundation in the mid first century C.E. to its several phases of collapse, followed by the subsequent construction of the mill with horizontal water wheel in late antiquity or the Early Medieval period. The bridge is one of the largest of its kind in North Africa. It thus is surprising that very little has been published on this important monument, which is also reflected in the relatively short literature review in this book’s chapter 1. In the first volume of the Simitthus series, the bridge and mill were explored only briefly (J. and G. Röder, “Die Antike Turbinenmühle in Chemtou,” in F. Rakob, ed., Simitthus 1: Die Steinbrücke und die Antike Stadt [Mainz 1993] 95–102), probably with the expectation that more detailed work would be published separately—something this fifth volume of the series has finally accomplished.

The work, a collaboration between the Institut National du Patrimoine (INP) and the Deutsche Archäologische Institut (DAI), was long in the making. The survey on the bridge and mill started in the 1970s, but the publication of Hess’ work was not achieved until now, delayed due in part to her premature passing. This volume is largely based on Hess’ work, updated and expanded in parts by Müller. Contributions by Khanoussi focus on the early and later phases of the bridge and analyze the reused inscriptions and other spolia that were integrated into its architecture. It is divided into two parts: (1) an introduction, with the history and detailed architectural description and reconstruction of the bridge and mill and (2) appendices that include tables, plans, drawings, and photographs in black and white.

Chemtou is located in northwest Tunisia, on one of the few large and perennial rivers in North Africa—an area extremely rich in agricultural activity due to its fertile soils. The city was particularly famous for its yellow marble, which was quarried and exported throughout the Roman empire. Chemtou lay along two major routes: the first from Thabraca to Sicca and the second from Carthage to Hippo via Bulla Regia. The relationship between the road network of North Africa during the Numidian and Roman period and the importance of bridge constructions such as this one is discussed by Khanoussi in chapter 2. The river formed a considerable barrier to the marble trade and the movement of other goods. Khanoussi considers the construction of the first Roman-period bridge (pons vetus) in relation to the bridge construction in the Wadi Beja and the Wadi Mebuja (Algeria) during the reign of Tiberius. The Trajanic inscription of the bridge (pons novus) at Chemtou also contains indications that an earlier bridge existed (pons vetus). Khanoussi suggests that the pons vetus was part of the same construction program undertaken by the military to improve road networks.

In chapter 3, Hess briefly places the construction of the bridge in its historical context. The Medjerda River was (and still is) rather unpredictable due to strong seasonal floodwaters that repeatedly caused damage to the bridge. Problems started to arise almost from the beginning of the construction of the pons vetus in the mid first century C.E., when the river undercut the foundation of the piers. To solve this problem, a platform of mortared rubble was laid across the river bed during the construction of the pons novus in the Trajanic period, on which the remaining piers could be built. The bridge was completed by the military in 112 (CIL 8.10117), but structural problems evidently continued. Floodwater still caused considerable damage, resulting in a series of repairs until the reign of Diocletian, when, as Hess suggests, the last repairs appeared to have taken place.

The complex series of construction, damage, and repairs are described extensively by Hess, with contributions by Müller, in chapter 4. The architectural elements of the bridge, including the piers, the north and south bank walls, and the plateau, are described in great detail. Remnants of the bridge are particularly well preserved at the south bank, and they tell the story of the problems the strong waters caused the engineers over time and the many repair efforts that had been carried out. However, it remains unclear whether the bridge was held up by three or four piers.

Chapter 4 (63–8) focuses on the mill that was constructed after parts of the Trajanic bridge collapsed. The rectangular building (ca. 8.32 m x 10.65 m, max. ht. 3.30 m) was located on the northern river bank and was built using the remains from the north bank wall, which had substantially collapsed. The high-velocity flow of the river created by the positioning of the material from the collapsed river bank created ideal conditions for the mill. The difference in height (2.70 m) between the water level of the platform and the lower flow of the water was used to generate the power to work the horizontal wheel. Three channels, which narrowed closer to the wheel and included slots for sluice gates near the inlet, connected the mill to the river.

Interestingly, Khanoussi, in chapter 5, suggests that the bridge was maintained until the Vandal period, based on reused materials and inscriptions in the northeast bank wall. This is significant because it would move the collapse of the bridge into the mid fifth century C.E. and not, as Hess believed, in the fourth century C.E. Subsequently, the construction of the mill could be moved to the Early Medieval period, and not in late antiquity as previously assumed. Khanoussi also provides a useful catalogue of reused inscriptions (81–3).  

The reconstruction of the bridge and the mill are considered in chapter 6, predominantly based on Hess’ reports and findings. Sections of the report that were later reworked by Müller are in italic type to distinguish them. The mechanics of the mill are also described in this chapter (95–6).

While the book is certainly impressive in conveying the architecture of the bridge and mill in considerable detail, Müller also clearly defines the scope and limitations of the volume (2–4). The information in the book is based on the work of Ulrike Hess, whose sudden death in 2006 interrupted work on the publication. It is important to stress that the work on the bridge and mill was Hess’ first academic endeavor. She undertook this work primarily alone, which, in itself, is a remarkable achievement. However, her untimely death and her inexperience in academic writing led to some shortcomings in the volume. When analyzing the materials left behind by Hess, it was sometimes difficult to see what were her own thoughts and what may have come from other sources. In addition, some of the original notebooks, which contained height measurements, could not be found. Some measurements were later retaken but, unfortunately, the northern area of the bridge and the mill could not be measured again, and the measurements are consequently missing from the volume’s plans. Weaknesses of Hess’ work are indicated throughout the book where appropriate, such as in chapter 4 where some of her architectural descriptions of the south bank wall do not match the evidence of the actual remains (39–40).

It appears that the scope of the initial project, which started in 1974, was too ambitious, resulting in Hess’ work never being completed. Beyond recording and analyzing the many construction phases of the bridge and attempting a reconstruction, she also had wanted to explore the influence the bridge had on its surrounding topography and to draw comparisons with contemporary bridge construction. On top of all this, she aimed to construct a model to visualize the impact the force of the water had on the structure. The complexity of the bridge’s construction and repair contributed to the fact that some initial research questions were never fully addressed. While this book does not answer these questions (and this was clearly not the aim), it can certainly help researchers tackle some of these questions in the future.

The audience for this book will primarily be experts on ancient architecture, especially bridges, and on water management techniques. Its attractive features are the detailed plans, drawings, tables, and photographs (including images from the 1970s) appearing throughout the book, and the appendices, which may also appeal to nonspecialists. Müller and Khanoussi have produced a publication that reflects the huge amount of work and effort Hess had devoted to her study. They succeeded in preserving her own work and viewpoint while simultaneously advancing or correcting certain aspects to bring it up-to-date with current research. Today, the bridge is inaccessible for study due to dense vegetation, mud, and rubbish surrounding its foundation. Therefore, the particular importance of the book lies in making information about the bridge and mill available and firmly placing it back onto the research map.

Julia Nikolaus
School of Archaeology and Ancient History
University of Leicester
jsn13@le.ac.uk