Famine, fever, flood, and conquest: the impact of natural disasters on the ninth-century rise of the Vikings in the Carolingian Empire according to the Royal Frankish Annals, the Annals of Xanten, the Annals of St Bertin, and The Annals of Fulda
Events characterised as “natural disasters” now had an impact on early medieval Europe (c. AD 476-1054), but previous attempts to measure said impact have been hindered by ambiguous terminology. This study reviews the modern mainstream concept of “natural disaster,” defined most broadly by The Asian Natural Disaster Reduction Center, and redefines it to fit within a medieval setting. Since the only clearly discernible impact of early medieval natural disasters appears to be exploitative political responses, it emphasises their cultural rather than environmental impact. A brief review of a selection of written sources suggests two particularly high-profile links between disasters and exploitative raids by the Scandinavian raiders now known as Vikings: the first on Lindisfarne, Northumbria, in AD 793 and the second on Dorestad, Frisia, in AD 834. The two disasters, a famine and a flood, would have weakened each populace physically, but would have also weakened their resolve and capacity for defence. Informed by the emphasis of later military strategists, the focus of this study becomes the possible exploitation of disaster-induced weaknesses by these warbands. A range of medieval written sources is then examined, but because only annals provided by Continental Europe’s contemporary Carolingian Empire provide the necessary extended run of precise data within a clear timeframe, the geographic focus is pinpointed upon the Empire. As the volume and detail of relevant data is at its peak before the Treaty of St. Claire-sur-Epte, when Charles the Simple granted the Viking leader Rollo of Normandy and that expanded to become the duchy of Normandy, the focus was further refined to the period before AD 911. By extracting, collating, coding, and then charting annalistic data for disasters and raids, and by using deaths of politically significant individuals and Frankish aggressions as controls, a methodology is devised to investigate the disaster/raid correlation. As the relative severity of these disasters remains unclear, corroboration is sought from non-narrative sources. While dendrochronology, (the science of tree rings), is used to help establish the broad climatic background, it does not allow for precise assessment of disaster severity. The embedded nature of Christian symbolism within Carolingian culture, however, allows for a subjective but more secure interpretation of severity through intertextual comparison of annalistic descriptions of disasters with the language of the Bible. The charted data is then revisited to find potential links between disasters and attacks, leading to the identification and presentation of four extensive case studies. The geographical, political, and climatic situation are all assessed along with the disaster’s likely severity, then the attack is modelled in light of military theory to assess whether the disaster created an exploitable weakness. In all four examples this is found to be the case. Thus, the thesis confirms that one of the most visible impacts of natural disasters in Early Medieval Europe was their potential for exploitation for political gain. By then investigating the geopolitical significance of these exploited disasters, the study then points to a possible loosely coordinated military strategy against the Carolingian Empire, challenging current theories on the origins of the Viking Age in Continental Europe. Further studies into the exploitation of natural disasters would therefore provide a path into understanding political developments in early medieval Europe and especially the Viking Age.