When he first started ruling Flanders there were a number of very damaging Viking raids. They everywhere except the area north of the Somme river. By 883 Baldwin was forced northward to the flat marshes of Flanders which became the territory most closely associated with the counts of Flanders from then on. Baldwin had built a series of wooden at Saint-Omer, Bruges, Ghent, and Courtrai. He also seized those lands and fortresses abandoned by royal and church officials. Baldwin had many of these same citadels used by his government, militia and local courts.