In the two centuries before the Norman invasion of England, Anglo-Saxon and Viking forces clashed repeatedly in battle, with mixed success for both sides. After the Vikings defeated three out of the four great Anglo-Saxon kingdoms and came close to defeating the fourth in the 860s and 870s, they conquered and settled large areas of England. Drawing upon historical accounts from both English and Scandinavian sources, and on archaeological evidence, Gareth Williams presents a detailed comparison of the weaponry, tactics, strategies, and underlying military organization of the Anglo-Saxons and Vikings, and considers the developments which took place on both sides between the arrival of the Vikings' "Great Raiding Army" in 865 and the battle of Stamford Bridge.