A new light on early medieval North Frisia : Harbours and trading sites on the islands of Föhr and Sylt

During the years of 2013-2018, the North Sea Harbour Project investigated early medieval settlement sites of the 7th-11th centuries along the German North Sea coast with a methodological bundle of archaeological and geophysical surveys, geoarchaeological investigations of their local settings and archaeological excavations. One of the core research areas were the North Frisian Islands of Föhr, Amrum and Sylt, which have a unique setting in the German Wadden Sea area. The islands consist of elevated Pleistocene moraine cores with adjacent marshes and easy access to the open sea. Their topography offers favoured settlement locations with high arable land and fertile pasture in the marshes. Natural harbour situations like small rivers and tidal creeks through the marshland provide navigable access to the maritime trade networks along the North Sea coast. It was possible to investigate sites at Witsum, Nieblum and Goting on the island of Föhr and Tinnum and Wenningstedt on the island of Sylt. The surveys revealed a pattern of enclosed village complexes, open complexes with separated functional areas and protective ring fortresses. During the 8th and 9th centuries, the sites show a high level of specialised craft production focused on textiles and amber, but also numerous imports and the refining of imported raw materials, especially glass bead production. It is argued that these sites acted as trading sites for production and re-distribution on a local and regional level, firmly connected to the maritime trade along the North Sea Coast and the nearby emporium of Ribe. The high level of trade and production activities can be traced until the middle of the 9th century, when the maritime trade routes shift focus towards Hedeby and bypass the islands. Subsequently, settlement structures change and the harbour locations lose relevance, although the strong involvement of North Frisian residents in the maritime trade is maintained throughout the Viking Age.