Baldwin II was born around 865 to Margrave Baldwin I of Flanders and Judith, daughter of Emperor Charles the Bald. The early years of Baldwin II's rule were marked by a series of devastating Viking raids into Flanders. By 883, he was forced to move north to Pagus Flandransis, which became the territory most closely associated with the Counts of Flanders. Baldwin constructed a series of wooden fortifications at Saint-Omer, Bruges, Ghent, and Kortrijk. He then seized lands that were abandoned by royal and ecclesiastical officials. Many of these same citadels later formed castellanies which housed government, militia, and local courts.