Recent network-based approaches to the ancient and medieval past have prioritised models of connectivity and diffusion that emphasise weak ties and brokerage (e.g. Malkin, Constantakopoulou & Panagopoulou (eds), Greek and Roman Networks in the Mediterranean, 2009; Malkin, A Small Greek World, 2011). Networks and the Spread of Ideas in the Past reframes this paradigm by demonstrating that the adoption of complex religious, ideological and social innovations depends on strong, trust-based networks rooted in place, ritual, narrative and institutional authority.
By integrating formal network analysis with historically grounded case studies ranging from Iron Age sanctuaries to late medieval urban communities, the volume advances a theoretically robust model of complex contagion that accounts for persuasion, resistance and belief formation, offering a methodological framework for reassessing how ideas achieve social durability rather than mere circulation. Whereas Malkin’s network model explains how the Mediterranean became interconnected through weak ties and brokerage, and Collar’s earlier work (Religious Networks in the Roman Empire, 2013) demonstrated how religious practices moved within those structures, this volume shifts attention to the social mechanics of belief itself. By foregrounding strong ties, trust and repetition, it argues that complex religious and ideological change cannot be explained by connectivity alone, but requires dense, emotionally grounded networks capable of sustaining persuasion and commitment over time.
Ch. 1, by Anna Collar, sets out the book’s core argument: complex ideas such as religious belief and ideology spread only when embedded within strong social ties that generate trust, emotional commitment and repeated reinforcement. C. critiques overreliance on small-world and weak-tie models in archaeology and history, arguing instead for attention to places, stories and systems that create ‘wide bridges’ for complex contagion. As C. argues, strong ties are essential for adoption, not just transmission. Across periods and case studies, the book shows that while weak ties spread awareness, strong ties produce belief, trust and behavioural change. Whether the innovation is coinage, religious imagery, mystery cults, Christianity, legal norms or heretical belief, adoption happens inside dense, emotionally meaningful networks.
Ch. 2 by Megan Daniels examines how Iron Age sanctuaries functioned as elite strong-tie hubs through which ideological symbols, such as the nude standing female, were transmitted and reinterpreted across the Mediterranean. Ch. 3, by John Mooring, shows how the diffusion of coinage in Archaic Greece relied on elite opinion leaders whose strong social ties, forged through panhellenic sanctuaries, enabled trust and local adoption of this economic innovation. In ch. 4, using epigraphic evidence and network metrics, Sandra Blakely and Joanna Mundy demonstrate how initiation into the Samothracian mysteries created durable transregional strong-tie networks, in which certain cities acted as brokers or bottlenecks, that underpinned political cooperation, mobility and shared religious identity.
These papers show how places matter because they manufacture strong ties. Sanctuaries, festivals, cities, churches and neighbourhoods are not passive backdrops. They create repeated interaction, generate shared memory, ritualise belonging, turn strangers into temporary kin. These places act as ‘wide bridges’, enabling complex contagion without relying on random weak ties. Part II of the volume focuses on storytelling and the power of the narratives that bind. Storytelling and ritual stabilise networks over distance. Narratives, myths, iconography and ritual practice allow communities to (1) remain coherent despite geographic separation, (2) recognise each other as belonging to the same moral universe, and (3) transmit ideas without direct contact. Objects, images and stories function as social glue.
In ch. 5, Christina G. Williamson argues that Hellenistic festivals reinforced existing inter-city strong ties by producing ritualised ‘portable communities’ that sustained shared narratives and collective identity. Kevin Stoba in ch. 6 shows how local conformity and innovation in Mithraic imagery emerged from dense strong-tie networks that shaped ritual practice more powerfully than regional or imperial frameworks. In ch. 7, Nathanael Andrade reconstructs the spread of traditions about the apostle Thomas. He shows that layered networks—commercial, ecclesiastical, diplomatic and pilgrimage—enabled narratives to evolve over centuries. Strong ties grounded in trust allowed local South Indian traditions to diverge from Mediterranean texts while remaining connected to them. This section shows how innovation is selective, local and negotiated. The book consistently rejects smooth diffusion curves, uniform adoption and simple centre→periphery models. Instead, innovations are reshaped locally, resisted or abandoned, integrated into existing habits (habitus). Change happens through negotiation, not replacement.
The final part of the volume analyses the structures that bind the systems. Ch. 8, by Rebecca Sweetman, examines how Christianity became materially embedded in cities through church construction. She argues that early Christian spread relied on strong local ties and memory-laden spaces, while later expansion used weak ties such as pilgrimage and trade. This highlights the interaction of social networks, urban topography and religious change. In ch. 9 Kilian Mallon analyses how Church councils and legal frameworks created and maintained Christian authority. Ecclesiastical law relied on dense networks of bishops and clergy, using strong ties to enforce norms across vast territories. Finally, in ch. 10, Esther Lewis applies network analysis to the persistence of Lollard belief in fifteenth-century Bristol. This reveals how heterodox ideas circulated through neighbourhood-level strong ties rather than marginal weak connections. In these chapters, we see how systems use networks to control behaviour. Networks are shown to enforce orthodoxy, regulate boundaries, marginalise dissent and stabilise power. Law, architecture, and institutions are network technologies built on strong ties.
Theoretically the book treats Mark S. Granovetter’s theory of weak ties as necessary but not sufficient (‘The strength of weak ties’, American Journal of Sociology 78.6 (1973), 1360–80). Weak ties connect clusters and enable fast spread of simple information, but they lack trust and persuasive power. Everett M. Roger’s theory of how innovation spreads through social categories (innovators, early adopters, early/late majority), driven by opinion leaders and social context (‘Diffusion of innovations’, in An Integrated Approach to Communication Theory and Research (2014), 432–48), helps explain who adopts innovations — but the book repeatedly shows diffusion is non-linear, contextual and trust-dependent. The book also demonstrates that ideas involving risk or behavioural change require multiple reinforcing exposures through strong ties (‘wide bridges’), not single weak-tie contacts. We could say that Centola’s complex contagion model is the unifying theory of the volume (D. Centola & M. Macy, ‘Complex contagions and the weakness of long ties’, American Journal of Sociology 113.3 (2007), 702–34).
Overall, the book demonstrates how network analysis is a heuristic, not a shortcut. Methodologically, the book argues that networks don’t replace interpretation, quantification must be paired with cultural meaning, and strong ties are harder to see archaeologically — but more important. The value of networks lies in asking better questions, not producing prettier graphs. Networks and the Spread of Ideas in the Past demonstrates that meaningful religious, ideological and social change does not result from connectivity alone, but from the sustained operation of strong, trust-based networks embedded in shared places, ritual practices, narrative traditions and institutional systems, through which innovations are repeatedly reinforced, negotiated and legitimised within communities across time and space.
