Henry III, Holy Roman Emperor
Various wars have been waged around the town, including the war of 1046 to 1056 between Baldwin V, Count of Flanders ("the Pious") and Henry III, Holy Roman Emperor, one battle of which was fought between Arques and Aire-sur-la-Lys. An artificial border was created on this occasion by digging a defensive canal called the Neufe-Fosse, which eventually became the Noeufossé canal.