Journal of Archaeology in the Low Countries 4-2 (April 2013)Laura I. Kooistra; Marieke van Dinter; Monica K. Dütting; Pauline van Rijn; Chiara Cavallo: Could the local population of the Lower Rhine delta supply the Roman army? Part 1: The archaeological and historical framework

3. The Roman army in the Rhine delta

3.1 Timber for forts and other military structures

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In the first 150 years A.D. at least seven wooden forts, with sizes between slightly less than one and two hectares, was located in the Rhine delta (Chorus 2007). Little is known about the fort at Bodegraven, but this fort also seems to have covered circa 1 ha (Van der Kooij et al. 2005). Near Katwijk, a stone construction was located that has been interpreted as a fort, and for which the date is unknown (e.g. Bloemers & De Weerd 1984; De Weerd 1986). It is also unknown whether this construction had a wooden predecessor. However, it is likely that a fort was located near the mouth of the estuary in the first century (Bosman & De Weerd 2004; Van Dinter in press). The fort near Vechten was probably larger than the other wooden forts in the delta. This is the oldest fort of the series and was built in the first decades B.C. or A.D. (Polak & Wynia 1991; Zandstra & Polak 2012).

The forts are not the Roman army's only structures. Watchtowers were built and quays were constructed. In the late first century, a road was built, partly with a wooden foundation, which connected the forts (Luksen-IJtsma 2010). Although the building activities did not all take place at the same time, there would have been periods when a large amount of construction wood was required, for instance when the forts and quays were constructed in the 40s A.D., after the Batavian revolt in A.D. 69/70 when many of the forts had burned down, and when roads were built in A.D. 99/100 and 123/125. In between these moments, construction wood would have been needed for renovations and when regiments changed.

The excavations near and in the forts of Alphen aan den Rijn (Haalebos & Franzen 2000; Polak et al. 2004) and Valkenburg (Glasbergen 1972; Glasbergen & Groenman-van Waateringe 1974; Van Rijn in prep.) have provided much information on the use of wood in a military context. Moreover, the Roman road has been investigated in various locations, and wood data have become available for other forts and several watchtowers near the fort of De Meern (Langeveld et al. 2010; Van der Kamp 2007; idem 2009). On the basis of more than 6000 finds of wood, Van Rijn (in prep.) has gained insight into the use of wood in military constructions in the Rhine delta and on the origin of the building material.

The research on the wood reveals that a wide spectrum of species was used for the construction of the forts and the accompanying quays between A.D. 40 and 70. Alder (Alnus), ash (Fraxinus excelsior) and elm (Ulmus) are the most common species. Oak (Quercus) and field maple (Acer campestre) were used relatively little (fig. 4a). A range of nine species was used for wickerwork, wicker mats and faggots, which adds to the total wood spectrum. The spectrum of used species shows similarities with that of riverine woodland on levees. Because part of the wood that is used in constructions is gnarly and crooked -- which would not be the case when it had been imported -- it is assumed that construction wood from the local woodland on the levees was used for the layout of the military defence system, perhaps complemented with alder wood from the flood basins and fen woodlands.

The period after circa A.D. 70 shows a strong increase in the use of alder, while ash, elm and field maple have almost disappeared (fig. 4b). This leads Van Rijn (2004; idem in prep.) to conclude that the riverine woodland on the levees had become scarce. From the late first century onwards the construction wood of alder was made out of trees which had more or less the same diameters, and consisted of straight stems without side branches. Van Rijn assumes that this alder wood came from coppiced alder woodlands which were managed by man, and which were probably located on the low-lying parts of the levees, in the flood basins and the fen woodlands. This assumption is extremely interesting, since coppiced woodland provides more suitable construction wood per hectare than natural woodland. The assumption that production woodland occurred in the Rhine delta as early as the late first century indicates that the landscape was at that time already adapted to the increased demand for construction wood.

The selection of oak in the period after A.D. 70 seems to have been limited to the construction and maintenance of roads and the river infrastructure, especially in A.D. 99/100 and A.D. 123/125 (fig. 4c-d). Research into the numbers and pattern of year rings has demonstrated that part of the construction wood came from woodland that had been harvested for wood before. Wood with several hundreds of year rings also occurs, and some of it has been investigated dendrochronologically. This has revealed that these oaks have come from natural woodland located in what is now the western part of the Netherlands (Visser 2009; Visser & Jansma 2009).

Apart from the use in building, wood was the main fuel for various activities, such as domestic use (cooking, baking and heating), craft activities and for cremations. Until now, little was known about the use and origin of firewood in military contexts.

The research on wood reveals that the construction wood for the forts and other military constructions, as well as for the wooden foundations of the road, is mainly of local or regional origin. This result fits with the historical research carried out by Kehne (2007, 324). He writes the following:

‘The system of mobilizing material resources to provision the Roman armies in the form of taxes in money and kind was imposed on the new provinces of Gallia, Brittania and Germania. For several reasons the Roman empire never developed an uniform and universally military supply system. The Roman empire had to meet logistic needs of the armed forces on a adhoc basis, with a lot of improvisation but constant improvement of the implemented institutions too.’

3.2 Timber for vici structures

It is likely that a camp village, or vicus, was located near each of the forts. Their remains have been found near the forts at Vechten (Vos 1997), Utrecht (Montforts 1995), De Meern (Langeveld in prep.), Woerden (Blom & Vos 2007), Zwammerdam (Haalebos 1977; Ploegaert 2006), Alphen aan den Rijn (Kok 1999), Leiden Roomburg (Brandenburgh 2006; Hazenberg 2000) and Valkenburg (De Hingh & Vos 2005; Vos & Lanzing 2000). However, our knowledge is fragmented, so that we know little about the size and chronology of the vici. Most of the vicus features, however, date from after circa A.D. 70 and from the second century A.D. (e.g. Blom & Vos 2007, 73, 414; Kemmers 2008).

Until now, traces of vici dating to the early or middle of the first century have only been found near the forts of Vechten and De Meern. A vicus seems to have been present at the fort of Vechten from the start (Hessing et al. 1997). The early vicus at the fort of De Meern seems to date to the middle of the first century. The structures consist of houses that have been built adjacent to one another, with yards at the back. The houses were inhabited for a maximum of ten years or so, and then abandoned (Langeveld in prep.). The absence of first-century vici near the other forts may be the result of lack of research or the many disturbances in the soil, which may have wiped out the oldest features. It is also possible that there were no permanent vici in the period from A.D. 40 until the end of the century, when the forts only served to protect shipping, with the exception of the large fort at Vechten (see below). Because only small sections of the vici have been excavated, their size is unknown. The inhabited area around the forts is estimated at several to several tens of hectares.

Unlike the forts, nothing is known about the use of wood in the buildings in the vici in the Rhine delta. Considering the wood use in the fort constructions, however, it seems likely that the buildings in the vicus were also mainly built with local wood. Wood for the early vici at De Meern and Vechten may have come from woodland on the alluvial ridges, although botanical research has shown that these were already largely deforested in the Late Iron Age (Groot & Kooistra 2009). Perhaps this is why alder from woodlands in the flood basins and fen woodlands was widely used in the first century, and oak -- being a far better building wood -- in a more restricted way.

3.3 Military population and their associates

An estimate was made of the size and composition of the Roman army and the associated vicus population, in order to gain an impression of the required amount of food. Based on their rather small size, it is assumed that the forts could house one cohors, circa 480 soldiers, but a number of soldiers per fort lower than 480 is likelier (Bechert 1983; Glasbergen & Groenman-van Waateringe 1974; Polak et al. 2004). De Weerd (2006) even argues that the forts were only occupied in the first century when it was necessary. The absence of vici in this period supports this hypothesis. Graafstal (in press.), however, has convincingly argued that the army controlled shipping on the Lower Rhine in this period. That means that the forts must have been occupied at least during the shipping season, from March to October (Fulford 2000, 42; Vegetius book IV, 39). From the end of the first century, the function of the forts changed, although the size of the forts stayed roughly the same. This makes it likely that the size of the army also stayed the same.

Only the fort Vechten was almost certainly larger. Indications for this exist especially for the period after A.D. 70 (Polak & Wynia 1991; Zandstra & Polak 2012). It is almost certain that the cohors I Flavia Hispanorum equitata (480 infantry plus 120 cavalry) was stationed there. There are some signs that possibly somewhere in the same period cohors II Brittonum equitata milliaria (800 infantry plus 240 cavalry) was associated with the fort. After A.D. 125, the ala I Thracum (500 men cavalry) was probably stationed in Vechten for a while. It is interesting to note that the occupation of the fort at Vechten consisted at least partly of cavalry units, because it is generally assumed that most of the forts in the Rhine delta were occupied by infantry units.

When we include Katwijk and Bodegraven, there were ten forts between Vechten and Katwijk (fig. 1). Based on an occupation of a maximum of 1 cohors, circa 480 men, per fort and possibly double that number for Vechten, the maximum size of the delta army is estimated around 5000 men.

It is generally assumed that from the late first century onward, it was mainly auxiliary units that were stationed in the forts. The finds of military diplomas indicate that the army units were not local (Polak 2009; idem in press). Less is known about the composition of the army between circa A.D. 40 and the mid-80s. Tacitus’ mention that the Batavians were not allowed to be stationed in their own territory anymore after the revolt in A.D. 69 has led to the assumption that the auxiliary forts in the Lower Rhine delta were largely manned with local soldiers. However, there is no epigraphic evidence for this, although it is known that a large part of the Batavian and Cananefatian auxiliary units were stationed in Great Britain, for example, in the 40s and 50s (De Weerd 2006). Taking these considerations into account, it is likely that the size and composition of the army in the period from A.D. 40 to the mid-80s was similar to that of the following period.

However, there is a large difference in the size of the consuming population till circa A.D. 70 in comparison with the end of the first century onwards. As has been described above, most vici, except those at Vechten and temporarily at De Meern, date after A.D. 70. The civilian settlements that arose around the forts had a military status and were inhabited by people related to the army (Sommer 1984; idem 1991): craftsmen, traders and family members of the soldiers. Although little is known about the size of the population of the vici near the forts in the Rhine delta, this is likely to have been similar to that elsewhere in Europe. That means that in later times the number of people living in the vicus was more or less equal to that of the garrison in the adjacent fort. The composition of the vicus population is a different story. While the people stationed in the forts were mostly men, men as well as women and children lived in the vici.

In short, the consuming population in the Lower Rhine delta from circa A.D. 40 until the end of the first century probably consisted of around 5000 soldiers and 500 to 1000 civilians, comprising men, women and children. It is possible that the number of consumers nearly doubled in the late first century to around 5000 soldiers and as many vicus inhabitants. Considering the presence of cavalry units, especially in Vechten but perhaps also small units in other forts, it is likely that horses, which may have required extra feeding, were kept in the forts.

3.4 Food for soldiers and vicus inhabitants

Various Roman authors have written about the quantities and the composition of the soldier’s diet. In the second century B.C., Polybius mentions circa 840 grams (converted) of wheat per day for an infantry soldier, 1.7 kg wheat for an auxiliary cavalry soldier and his servant(s) plus circa 6.3 kg barley for his horse and pack animals (Polybios The Histories 6.39; converted to grams in Erdkamp 1998, 28). As far as meat is concerned, Polybius writes about special spaces within a Roman camp that were reserved for cattle (Polybios, The Histories 6.31). In the mid-first century B.C. Caesar wrote that he regularly supplied his soldiers with vegetables and meat, besides cereals (Caesar, De Bello Civilli 3.47; see also the discussion in Erdkamp 1998, 31-32). Inventory lists for the army from other periods and regions show that the army was supplied with vegetables, fruit and nuts (Davies 1989, 198-199).

Nevertheless, cereals seem to have been the main part of the soldier’s diet in all centuries of the Roman empire's existence. Under emperor Hadrian, a century and a half after Polybius, a soldier's diet consisted of cereals, bacon, cheese and sour wine (Aelius Spartianus, Scriptores Histora Augustae Vita Hadriani 10.2). Vegetius, living in the fourth century, but using sources from earlier centuries, stated that there should be enough supplies of grains, sour wine, wine and salt at all times (Vegetius, De Re Militari 3.3), and when a fort was threatened to be sieged, supplies should be stored within the fort, consisting of enough food for horses and for the soldiers enough cereals, fruit, wine and sour wine. Pigs and other animals should be slaughtered to obtain a good supply of meat (Vegetius, De Re Militari 4.7). Olive oil is not named in these sources, although it is likely that this product was part of the basic soldier's diet. A quote from Tacitus is interesting with regard to the necessary amounts of food that should be in store. Tacitus writes that every Roman fort in Great Britain under the governorship of Agricola (between A.D. 78 and 84) was to have enough supplies for a year (Tacitus, Agricola 22.2-3), which amounted to circa 333 kg of cereals per soldier per year (Davies 1989, 187). Quantities are also mentioned in the Egyptian papyri from the fourth century A.D. They describe that a soldier had a right to 969 grams of cereals per day (=3 Roman pounds); 646 grams (2 Roman pounds) of meat or bacon, 1.1 litres of wine and 0.07 litres of oil (Garnsey & Saller 1987, 83-104).

Whether the sources date to the second century B.C. or the fourth century A.D., each soldier had to be supplied with 800 to 1000 grams of cereals a day. Less is known about the quantities of the other required food products. When we consider that 1 kg of cereals provides 3000 to 3300 kCal of energy (Bloemers 1978; Bakels 1982), and that an active, young adult man uses between 3000 and 3600 kCal of energy (Den Hartog 1963, 78-79; Gregg 1988, 143; Roth 1999), it becomes clear that cereals were the most important food for the Roman soldier (Kooistra 2012). This does not deny that meat products, fruits, nuts, vegetables, wine and olive oil were also substantial ingredients of the soldier’s diet. Some of the ingredients belonged to the official soldier’s diet. In addition, in times of peace soldiers could buy food themselves in the vici surrounding the forts. The now famous writing tablets from Vindolanda and other letters reveal that the soldiers also used family and relations to supplement their daily diet (Bowman 2003).

Analysis of the archaeobotanical and archaeozoological data from military sites in De Meern, Woerden, Zwammerdam, Alphen aan den Rijn, Leiden Roomburg and Valkenburg have given us insight into the food pattern of the military community in the Rhine delta. The archaeozoological research shows that in the start-up phase of a fort, relatively high amounts of pig and chicken were eaten (Cavallo et al. 2008). Once established, cattle became the main meat supplier. This applies to both the first and second centuries. Perhaps this can be explained by an insufficiently stable supply of animal products in the establishment phase of a fort. The soldiers would therefore have brought chickens and possibly pigs. Both these animals are fast breeders and require relatively little attention, which means that they could serve as temporary food until the supply lines had been established and the local population could take over (part of) the food production.

The archaeobotanical research (Kooistra 2009; idem 2012) shows that until the end of the first century (circa A.D. 70), there is a broad cereal spectrum in the forts, consisting of bread wheat (Triticum aestivum), emmer wheat (Triticum dicoccon), barley (Hordeum), spelt wheat (Triticum spelta), millet (Panicum miliaceum) and oat (Avena). The weeds found among the cereals indicate that part of the cereals was imported from Gaul. Since bread and spelt wheat are almost absent in agrarian settlements to the north and in the coastal, peat and river area south of the Rhine, it is assumed that these cereals were imported. Apart from remains of cereals, pulses, nuts, fruits and herbs have been found in the forts. Only Celtic beans (Vicia faba var. minor) could have been supplied by the agrarian settlements in the region. The other listed vegetable food products were not grown in agrarian settlements at this time, and must have been imported. At the end of the first century, the supply of cereals changed. In the forts, only bread wheat, spelt, emmer and barley are now found, with the first two cereals being imported, while the latter two could have been supplied by agrarian settlements in the region. From the second century, some Mediterranean herbs were grown in agrarian settlements to the south of the Rhine. Orchards for fruits and nuts can only be found in the southern and eastern parts of the province of Germania inferior. Both in the first and second centuries, part of the vegetable food products could have been sourced from the region, and part was imported. How much was imported and how much could have been local cannot be established purely by archaeobotanical research.

The food consumed by vicus inhabitants has not yet been discussed. Nothing is known on this topic from historical sources. The vici inhabitants were entirely dependent on the forts, since most of the population consisted of traders, craftsmen and relatives of the soldiers. There are no indications from archaeological research that there were any farmers living in the vici, growing cereals or breeding livestock. There are some indications for gardens where vegetables and herbs could have been grown (Van Amen & Brinkkemper 2009). However, it is generally assumed that the vicani were food consumers, and that means that they were also mainly dependent on the supply of food by the local agrarian population or on imports over longer distances. The relation between soldiers and vicani was probably so close that most of the vicus population would have moved when army units were transferred. This interconnection between soldiers and civilians makes it likely that their dietary habits were similar. This idea is supported by archaeozoological and archaeobotanical research. This has shown that the same food remains are found in the vici as in the military contexts (Kooistra 2009).

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