This paper proposes to proceed from a rather metaphorical application of network terminology on polities and imperial formations of the past to an actual use of tools and concepts of network science. For this purpose, a well-established network model of the route system in the Roman Empire (ORBIS) and a newly created network model of the infrastructural web of Imperial China are visualised and analysed with regard to their structural properties. Findings indicate that these systems could be understood as large-scale complex networks with pronounced differences in centrality and connectivity among places and a hierarchical sequence of clusters across spatial scales from the over-regional to the local level. Such properties in turn would influence the cohesion and robustness of imperial networks, as is demonstrated with two tests on the model´s vulnerability to node failure and to the collapse of long-distance connectivity. Tentatively, results can be connected with actual historical dynamics and thus hint at underlying network mechanisms of large-scale integration and disintegration of political formations.

Ancient and medieval harbours connected via navigable and terrestrial routes could be interpreted as elements of complex traffic networks. Based on evidence from three projects in Priority Programme 1630 (Fossa Carolina, Inland harbours in Central Europe and Byzantine harbours on the Balkan coasts) we present a pioneer study to apply concepts and tools of network theory on archaeological and on written evidence as well as to integrate this data into different network models. Our diachronic approach allows for an analysis of the temporal and spatial dynamics of webs of connectivity with a focus on the 1st millennium AD. The combination of case studies on various spatial scales as well as from regions of inland and maritime navigation (Central Europe respectively the Seas around the Balkans) allows for the identification of structural similarities respectively difference between pre-modern traffic systems across Europe. The contribution is a first step towards further adaptions of tools of network analysis as an instrument for the connection and comparison of data across the projects of Priority Programme 1630.

Draft for: “Complexity: a new framework to interpret ancient economic proxy data”. Book project and conference: Sagalassos, Sept. 11th-12th 2015 (cf. http://www.rsrc.ugent.be/sdep/complexity) Abstract: Based on the assumption that economic complexity is characterised by the interactions of “economic agents (who) constantly change their actions and strategies in response to the outcome they mutually create”, this paper presents how network models can be used a “proxies” for the mapping, quantification and comparison of pre-modern economic complexity. Network analysis provides tools to visualise and analyse the “inherent” complexity of various types of data and their combination (archaeological, geographical, textual) or even of a single piece of evidence. Equally, the relational approach invites to a structural and quantitative comparison between periods, regions and the economic systems of polities and empires. An increasing number of proxies of this kind allow us to capture the trajectories of economic complexity from antiquity into the middle ages beyond metaphors.

Published in: Sven Kalmring · Lukas Werther (eds.), HÄFEN IM 1. MILLENNIUM AD. STANDORTBEDINGUNGEN, ENTWICKLUNGSMODELLE UND ÖKONOMISCHE VERNETZUNG. Mainz 2017, see: https://shop.rgzm.de/de/wissenschaftliche-reihen/rgzm-tagungen/haefen-1-millennium-ad (in German) Embedding certain harbors into a large-scale system of logistics could illustrate the peculiarities and similarities between local and empire-wide economic patterns. Such kind of methodology also helps us to find an explanation for the existing differences. Tracing the divergences in the distribution of Late Antique pottery in Butrint, Durrës and Shkodër leads to the conclusion that Durrës and Shkodër belonged to a transport cluster that covers the Adriatic Sea and Northern Epirus. Butrint on the other hand belongs to another cluster comprising the northwestern areas of Central Greece, Northern Peloponnese and the Ionian Sea. The distribution of coins minted in Syracuse from the 7th to 9th century and found during excavations in Butrint underlines the importance of the sea route Sicily – Southern Italy – the Ionian Sea – the Aegean and corresponds to the ORBIS Model and the data about the networks of the kommerkiarioi. The findings of Glazed White Ware I produced in Constantinople in various Balkan settlements such as Butrint, Debeltos and Anchialos demonstrate the networks maintained by the capital. The different types of cluster dealing with connections and communication via sea routes offered the base for the reestablishment of trade networks in the Mediterranean since the 9th century. As Michael McCormick states: »by 800, multiple circuits were connecting again, linking the growing agrarian economies and political societies of Western Europe to each other, and back to the Middle East.« This process of reintegration of local maritime networks in the economic system of the High Middle Ages represents one of the main objectives of the SPP 1630.

Talk at the CML and Where East Meets West Seminar, University of South Denmark (Odense), August 19th 2015, see: http://www.sdu.dk/en/Om_SDU/Institutter_centre/C_cml/Calendar/WEMW

Draft for the workshop: “Linking the Mediterranean. Regional and Trans-Regional Interactions in Times of Fragmentation (300 -800 CE)”, Vienna, 11th-13th December 2014 (see: https://www.academia.edu/9238221/Linking_the_Mediterranean_Regional_and_Trans-Regional_Interactions_in_Times_of_Fragmentation_300_-800_CE_) While Michael McCormick in his “Origins of the European Economy” has highlighted the dynamics of connectivity between Western Europe and the Eastern Mediterranean after the fall of the Western Roman Empire and thus also ultimately confuted the thesis of Henri Pirenne on a destruction of the unity of the Mediterranean in this period, a similar approach towards the connections within the Eastern Mediterranean and beyond would provide equally significant results for the “Origins of Eurasian Economy”. In my paper, I will focus especially on the mobility of individuals, objects, technologies and ideas between the spheres of Byzantium respectively Persia and Central Asia and the “Far East”, traditionally connected with the master narrative of the “Silk Road”. The notion of the “Silk Road” suggests linear routes between two localities, while recent scholarship has illuminated the “multiplexity” of commercial, political or religious ties among places on the local, regional and trans-regional level. Within these complex and dynamic networks over several spatial and temporal scales emerged processes of religious, intellectual or artistic diffusion. I survey some selected developments and intensities of long-distance connectivity, especially from the perspective of some important intermediary regions, for the period between 550 and 850 CE. Second, I focus on what C. A. Bayly in his “Birth of the Modern World” (2003) has called the lateral and the vertical dimension of phenomena of “global” diffusion and exchange: the spatial range of mobility and communication of individuals and objects which connected localities and clusters of localities along the “Silk routes” – and the vertical dimension of the impact of the material and immaterial artefacts of these exchange in the respective local societies. Finally, I link these observations with some discussions on the character of exchange and socio-economic integration in the Roman and Post-Roman world as well as with some general models of connectivity.

Selected bibliography on historical and archaeological network analysis, compiled for introductory workshops and course; besides historical and archaeological studies using concepts and tools of network theory, the focus is on introductory works and important methodological studies.

Press release of the Austrian Academy of Sciences (25 October 2018): https://www.oeaw.ac.at/oesterreichische-akademie-der-wissenschaften/die-oeaw/article/rom-und-china-weltreiche-funktionierten-wie-komplexe-netzwerke-1/ on the following publication: https://arxiv.org/abs/1809.08937

This paper surveys the use of Network Science, especially the role of Archaeological Networks to the study of Archeology and Ancient History. Network thinking and network sciences are valuable methodologies and analytical techniques to apply to the study clay lamps in the framework of the Roman economy. The recent application of network analysis in Antiquity and Archaeology has demonstrated that there are a variety of approaches to recognizing network patterns or thinking about phenomena as products of networked processes. Provincial connectivity is one of the most debated aspects of Roman economics, and ceramic consumption patterns in the interior and coastal regions of Africa Proconsularis have proven to be very different. The dominant tendency to turn to the communities formed and structured around native identities, especially those based in the major urban centers and larger areas, seems to establish itself as an argument for the economy and exchanges of the Roman Empire. These types of networks helped to spread ideas and religious symbols through clay lamps. Africa Proconsular demonstrates evidence that the ceramic workshops emerged as networks in order to establish themselves seeking to meet the Mediterranean demand and religious consumption.

Draft for the Workshop “Comparative Studies in Imperial History (Part I) All under Heaven? The Empire’s Spatial Dimensions”, Eisenach, June 30th-July 2nd 2015, organised by Prof. Michal Biran (The Hebrew University) and Prof. Eva Cancik-Kirschbaum (Freie Universität Berlin), cf. http://mongol.huji.ac.il/projects/comparative-studies-imperial-history The aim of this paper is (of course) not a comprehensive analysis of the Medieval Roman Empire of the East, commonly called the “Byzantine Empire” as spatial phenomenon; especially in the “Vienna School of Byzantine Studies”, entire books (Johannes Koder´s “Lebensraum”) have been written about this and a fundamental long-term project (Tabula imperii Byzantini) is devoted to the historical geography of Byzantium. I will discuss some general principles of spatial organisation and perception as can be reconstructed from Byzantine sources, furthermore the definition and dynamics of frontiers and finally the significance of the centre (Constantinople) and its demands for the spatial framework of imperial politics. The chronological focus will be on the centuries from the inauguration of Constantinople as new capital (330 CE) up to Fourth Crusade in 1204 CE (and within this period, even more on the 6th-11th centuries); after that time, the permanent political fragmentation of the former core sphere of the Byzantine Empire provided a very different spatial framework (with which I have also dealt in an earlier study ). Furthermore, I will deal more with the frontiers and relations of Byzantium to the East, where also Byzantine authors identified (competing) polities of a similar imperial quality, than with the connections to and conflicts with medieval Western Europe. I hope to be able to demonstrate how specific aspects of Byzantium´s spatial dynamics can be integrated in a more general comparative discussion of empires as spatial phenomena; in the conclusion I will try to raise some questions which may be of relevance in this regard.