Already in the early Middle Ages, the cities of Zutphen (as a center of power) and Deventer (as a trading center) flourished thanks to their location on the IJssel. The Vikings could also reach and plunder the settlements via the IJssel. A documented looting took place in 882. Archaeological traces of it have been excavated in Zutphen and Deventer. Later, in the time of the Hanseatic League (+/- 1250-1450), the IJssel was an important international trade route; The cities along the IJssel: Doesburg, Zutphen, Deventer, Hattem, Zwolle and Kampen were therefore affiliated with the Hanseatic League.