We need not travel far to find examples of their barbarism. Their cruelty in warfare is a commonplace among the historians of the period. When the Irish found the Danes cooking their food on spits stuck in the bodies of their fallen foes (_v. supra_, p. 55) and asked why they did anything so hateful, the answer came 'Why not? If the other side had been victorious they would have done the same with us.' The custom of cutting the blood-eagle (i.e. cutting the ribs in the shape of an eagle and pulling the lungs through the opening) was a well-known form of vengeance taken on the slayer of one's father if captured in battle, and is illustrated in the story of the sons of Ragnarr Loðbrók himself. Another survival of primitive life was the famous Berserk fury, when men in the heat of battle were seized with sudden madness and, according to the popular belief, received a double portion of strength, and lost all sense of bodily pain, a custom for which Dr Bugge finds an apt parallel in the 'running amok' of the races of the Malay peninsula. Children were tossed on the point of the spear and the Viking leader who discouraged the custom was nicknamed _barnakarl_, i.e. children's friend. In contrast to these methods of warfare stands their skill in fortification, in which they taught many lessons both to their English and to their Frankish adversaries, their readiness in adapting themselves to new conditions of warfare (_v. supra_, p. 46), and their clever strategy, whereby they again and again outwitted their opponents.