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.