However, their art of war is mainly influenced by the military innovations of the Carolingian empire and so their armies have a good balance between cavalry and infantrymen. The Frisians have maintained cultural and commercial ties with the Anglo-Saxons from the other side of the English Channel. Defeated by the Franks, their country is now under the rule of a Frankish governor. The Frisians are the inhabitants of an important trading region along the southeastern coast of the North Sea, from the north of Frankia to the border of Danmark. The Norse shield-wall is considered almost impossible to overcome. They are skilled archers and, although in during expeditions they send out mounted scouts, in battles they dismount to fight on foot. The Great Heathen Army, led by the sons of Ragnar Lodbrok, have invaded the Anglo-Saxon kingdoms and now threaten the British Isles. Their naval superiority allows them to raid the coasts of the other kingdoms, but despite their reputation as blood-thirsty looters, the Vikings are excellent traders that have begun to colonize the frozen islands of the North Sea. The Norsemen are pagan peoples with a Germanic heritage who inhabit Scandinavia, comprising the realms of Northvegr and Danmark. Viking Conquest introduces six historically accurate cultures.