the Seine below Nogent-sur-Seine and the lines of the Meuse and Scheldt, was also cut into on the north by the rise of Flanders, and on the west by that of Normandy which at the same time reduced the former area of Neustria by one-third, while to the east the March or Duchy of Burgundy was taking shape in that part of ancient Burgundy which had remained French. The study of the rise of these great principalities is in the highest degree instructive, because it enables us to point out the exact process by which the diminution of the royal power was being effected.
For Flanders it is necessary to go back to the time of Charles the Bald. About 863 that king had entrusted to Count Baldwin, whose marriage with his daughter Judith he had just sanctioned, some counties to the north, among which were, no doubt, Ghent, Bruges, Courtrai and the Mempisc district. These formed a genuine "March," the creation of which was justified by the necessity of defending the country against the northern pirates. The danger on this side was not less serious than from the direction of the Loire, where the March of Neustria was set up, almost at the same time, for Robert the Strong. The descendants of Count Baldwin I not only succeeded in holding the March thus constituted, but worked unceasingly to extend its limits. Baldwin II the Bald (879-918), son of Baldwin I, took advantage of the difficulties with which Odo and Charles the Simple had to struggle to lay hands upon Arrus. In the year 900, Charles the Simple having intended, by the advice of Fulk, Archbishop of Rheims, to retake the town, Baldwin II had the prelate assassinated, and not content with keeping Artois, succeeded in fixing himself in the Tournaisis, and in getting a foothold, if he had not already done so, in the county of Therouanne by obtaining from the king the Abbey of Saint-Bertin. His son, Arnold I (918-964) shewed himself in all respects his worthy successor. Devoid of scruples, not hesitating to rid himself by murder of William Longsword, Duke of Normandy, whom he considered dangerous (942) just as his father had done in the case of Archbishop Fulk, Arnold attacked Ponthieu where he got possession of Montreuil-sur-Mer (948). Thus at that time the Flemish March included all the lands lying between the Scheldt as far as its mouth, the North Sea and the Canche, and by the acquisition of Montreuil-sur-Mer even stretched into Ponthieu.
This progressive extension towards the south could not be other than a menace to the monarchy. As in the case of Aquitaine, Lothair endeavoured to check it by a sudden stroke, which on this occasion was at least partly successful. In the first place he was astute enough to persuade Arnold I, now broken in spirit, it would appear, by age and the loss of his eldest son Baldwin, to make him a donation of his duchy (962). It was stipulated only that Arnold should enjoy the usufruct. Three years later on 27 March 965 Arnold died, and immediately Lothair marched into Flanders, and, without striking a blow, took Arras, Douai,
