Shaped by sea and settlement: Maritime landscapes and societal change in medieval Iceland and Brittany

This paper proposes a comparative analysis of landscape transformation and socio-environmental adaptation in early medieval Iceland (post-877 CE) and medieval Brittany (5th–15th centuries), focusing on how initial settlement practices catalysed long-term changes in land use, dietary strategies, and social organisation. In Iceland, palaeoecological proxies (tephrochronology, palynological data, δ13C/δ15N isotopes) reveal rapid deforestation, soil erosion, and shifts from birch-juniper shrublands to grassland-dominated systems following Norse settlement, driven by livestock grazing and fuel demand. These changes correlate with the establishment of decentralised, household-based landnám farms, where resource allocation (e.g., marine vs. terrestrial protein) shaped hierarchical social structures and resilience to volcanic crises. In Brittany, by contrast, earlier and more gradual agricultural expansion under feudal systems fostered nucleated villages, with mixed farming economies anchored in cereal cultivation and woodland management. The paper will contrast Iceland’s “biotic revolution” – marked by volcanic forcing and anthropogenically accelerated erosion – against Brittany’s slower, climate-modulated transitions, highlighting the interplay between human agency and environmental constraints.Key themes include:Landscape legacies: How initial land clearance strategies (Iceland’s landnám and Brittany’s Roman-era villae) constrained later adaptation to the Little Ice Age. Dietary resilience: Dependence on marine resources in Iceland vs. agricultural diversification in Brittany, as evidenced by isotopic and zooarchaeological data. Social feedbacks: The role of environmental stress (volcanism, soil depletion) in reshaping power dynamics, including Iceland’s shift toward ecclesiastical governance and Brittany’s manorial intensification. By integrating climatic, ecological, and archival proxies, this cross-regional framework aims to disentangle anthropogenic and natural drivers of medieval socio-environmental change and offers insights into premodern resilience strategies amidst climatic variability and social upheaval.