The Fight for Nordalbingia: Reconstruction and Simulation of the Danish-Obodrite Attack on the Frankish Fortress of Esesfelth in AD 817

Abstract

It is possible to gain insight into Frankish-Danish relations in Nordalbingia during the early 9th century based on archaeological excavation results and written sources. Such relations were characterised by armed conflicts, political intrigue and shifting alliances. The Frankish fortress of Esesfelth had a key function during this time of unrest. Emperor Charlemagne built it in AD 810, partly to prevent Danish supremacy over the Nordalbingian Saxon territory north of the River Elbe, and partly as a starting point for incorporating it into the Frankish realm. The fortress was an exceptional defensive structure without any known contemporary parallels. As the centre of Frankish administration in Nordalbingia Esesfelth became the target of an attack by combined Danish and Slavic (Obodrite) forces in AD 817. To some extent, the attack can be reconstructed by interpreting excavation results, and simulated with the aid of military theory. The results also present an excellent opportunity to explore various fortification components in detail.