The Western Roman Atlantic Façade A study of the economy and trade in the Mar Exterior from the Republic to the Principate Edited by C. Carreras R. Morais BAR International Series 2162 2010 Published by Archaeopress Publishers of British Archaeological Reports Gordon House 276 Banbury Road Oxford OX2 7ED England [email protected] www.archaeopress.com BAR S2162 The Western Roman Atlantic Façade: A study of the economy and trade in the Mar Exterior from the Republic to the Principate © Archaeopress and the individual authors 2010 ISBN 978 1 4073 0706 0 Printed in England by Blenheim Colour Ltd All BAR titles are available from: Hadrian Books Ltd 122 Banbury Road Oxford OX2 7BP England www.hadrianbooks.co.uk The current BAR catalogue with details of all titles in print, prices and means of payment is available free from Hadrian Books or may be downloaded from www.archaeopress.com THE NATURE OF THE ROMAN TRADE IN THE ATLANTIC 1.3 TRANSPORTATION COSTS IN NW HISPANIA P. de Soto INTRODUCTION Modern studies on the configuration of communication and transport networks have become popular over recent To understand the importance of the Atlantic façade and years thanks to the innovation of GIS. This new approach its close relationship with the NW Peninsula it is to the study of transport networks derives in part from necessary, of course, to consider the question of transport Hagget (1969). He and others demonstrated that network in Roman times. Ringrose (1972) stated that peninsular morphology provides understanding of economic and stagnation between 1750 and 1850 was due mainly to a commercial structures across a wide range of territory. relative inability to adapt transportation to the With regards to a British case study, Haggett (1969) requirements of that period. In Roman times the physical concluded that the communications network gave and cost conditions shaped transport systems and primacy to London as a main vertex in the network. Later reflected the landscape and patterns of human settlement. on, in the 1970s, scholars realized that this primacy The close relationship between these two historic stemmed from an earlier period – Roman times. moments is based on the continuity of road networks from the Roman period to the XVIth century AD (Uriol, Dicks (1972) established that the communications 1985). Up to the XXth century the costs of land transport network of the Roman province of Britannia was hindered contacts between the centre and periphery of the organised according to a form of ‘tree shape’, in which Iberian Peninsula, with the only exception being the areas Londinium was located in a central position. His study located near rivers, which benefited from the low costs of analyzed the whole Romano-British road network in water transport (Carreras, 1997, 164). Roman times, with roads the simple branches of the network; like a river, the more tributaries a road had the Communication and trade in antiquity relied on three more important it was. Following this method, he reached main systems of transport. As the ancient sources relate, a conclusion that the communication network was the most economic form of transport – the fastest and organised according to three large axes that related the with most carrying capacity – was maritime navigation.1 capital, Londinium, with three other centres: Ebucarum This means of transport was especially employed in (York) through Ermine Street (Fens-Lincoln), Isca commercial relations of the Iberian Peninsula. The (Caerleon) through Silchester-Gloucester and Deva second most favoured inland transport was riverine; the (Chester) through Watling Road (St. Albans-Wroxeter). Iberian Peninsula rivers such as the Ebro, Tajo, Duero, According to Dicks (1972) this road pattern responded to Guadiana, Guadalquivir, Miño and its tributaries stood the first military requirements of the Roman occupation, out.2 Finally, the third means of communication was by although such axes were developed later to generate the land. Rome laid out a complex network of roads, internal economic relationships of Britannia. approximately 90,000 km of paved roads and an overall network of 300,000 km (Chic, 1993). In the case of In the present work, the methodology developed by these Hispania, the road networks were established sometimes British scholars will be applied to study how the NW of along pre-existing pathways, for instance the Via the Iberian Peninsula organized its communication Heraclea or the Via de la Plata (Silver way). However network. From the particular shape of communications in sometimes the roads were also built ex novo based on this geographical region, an attempt will be made to economic, military or political interests. recognize its key features and how they affect regional political and socio-economic aspects. Another important 1 On the importance, use and consequences of navigation in antiquity aspect in the study of the NW road network will be to see Rougé (1975); Pomey (1997). focus on the centrality of the different urban centres in 2 There is recent monograph on classical resources, history and rivers of the Iberian Peninsula in Roman times (Parodi, 2001). the territory. Such studies come from the concept of 31 THE WESTERN ROMAN ATLANTIC FAÇADE: A STUDY OF ECONOMY AND TRADE IN THE MAR EXTERIOR... Figure 1.3.2 Example of a graph diagram Figure 1.3.1 Example of an ordering diagram (Social Network) rating nodes according to with simple braches to the network its degree of centrality (Network Degree) Centrality Degree, employed in a so-called Social In our study, a methodological parallel becomes evident: Network Analysis (Freeman, 1979). Such analyses give the more transport infrastructures are associated with a values to each ‘node’ (or point to which more than one particular population centre, the better the accessibility roads converge) according to the number of total will be for its people and merchandise. The complexity of connections linked to it. Therefore the more connections the relationship increases when a correct network is received by a single node the more important it is. In defined from the archaeological and historical data, and other words it has a higher degree of accessibility or when trying to rate the diverse types of transport communicability.3 The origin of those analyses stem from employed. This will probably not affect the concept of “graph theory”, applied not only in mathematics but also the “degree of centrality” when arriving at either a in computer science. Graphs are understood as a secondary road or the existence of maritime port of collection of points (i.e. cities, people…) identified as interprovincial trade.4 From our study, it is believed that vertices or nodes, connected by arcs or lines, which the key urban centres in the NW transportation network identify relationships such a distance, cost (i.e. economic, in Roman times will stand out, as well as the territorial social…). organization in terms of mobility. Despite the widespread dissemination of these applica- As mentioned, our first step was to analyse the degree of tions nowadays, the theory was developed by Leonhard centrality amongst different cities, as well as their layout, Euler in 1736. He applied his theory to solve the commu- using the tree-branch theory proposed by Dicks (1972). It nication problems of the inhabitants of Köningsberg, who was attempted to find as many historical and built 7 bridges to optimise mobility. Afterwards, in the archaeological details as possible in order to understand th middle of XIX century, new intellectual challenges the communications layout (graphs theory) on which to related to transportation (i.e. Chinese postmen, base further study.5 travelling businessman) were solved by graph theory. In the XXth century, sociology and social network studies have helped develop the latest applications of TRANSPORT INFRASTRUCTURES graph theory. Those applications have helped us to (pre-Flavian period) understand interpersonal relationships, and they have even been employed to analyse Internet commu- Proper communications were set up in the NW peninsula nities. in the Flavian period, however their origins stemmed from previous periods. The development of Roman roads 3 This system of centrality is interpreted as the most intuitive way of in this region is obviously closely related to Roman state connectivity analysis (Freeman, 1979, 220) and was introduced by interests. However, in most cases they took advantage of Shaw (1954). But Nieminem (1974) was the one who defined a mathematic algorithm: Cd(Pk) = Σ a(Pi,Pk). Later, other types of analysis were established, such as Betweenness Degree or Closeness 4 In our case we added a different value to each point according to the Degree. All are used in the study of social networks due to those mean of transport and the road category (between 1 and 4); a node with functional components (influences and functions of individuals only one point (rated 4) could have more accessibility than a node with according to the degree of closeness). Because of the functional and three linked points (rated 1). economic components of our study, the analysis chosen is more related 5 It is not intended here to look in depth at the historic and to the potential of communicability amongst cities. archaeological data of the NW territories. 32 THE NATURE OF THE ROMAN TRADE IN THE ATLANTIC the primitive organization of the territory coming from continued along the Bay of Biscay (Atlantic route). This pre-Roman periods. route is referred to mainly by Caesar (CAES. Gal. 3.26.6), Strabo (STR. 3.4.18) and Orosius (OROS. Hist. With regards to the maritime communications, Atlantic 6.21.4), who describe contacts, exchanges and transport navigation is known from the Neolithic period, in which of troops between Cantabrians and the territory of some cultural influences such as megaliths or metallurgy Aquitania. are well identified (Naveiro, 1991, 135; Ruiz-Galvez, 1986, 24).