メルセン条約
During the period of West Frankish control under the Treaty of Meerssen, effective Frankish power in the area of the current Netherlands more or less collapsed. For two or more years a large Viking army, operating from a place on or near the Meuse called Ascloa (or Hasloa or Haslon), wrought havoc in the neighbourhood. The damage was such that the emperor, Charles the Fat was forced to assemble a large multinational army, that in 882 unsuccessfully besieged this island.