(The abbey was also exempt in Rouen, Amiens, Dorestad, and Maastricht.) Charlemagne wanted to have better control of this taxation process so he appointed abbots to fill this role.
The region comprising future Flanders was, from an economic point of view, a flourishing region, with a series of ports along the Scheldt river: Ghent, Tournai, Valenciennes, Cambrai and Lambres at Douai on the Scarpe and a number of seaports: Quentovic, Boulogne and Isère portus, a port at the mouth of the Yser.