Fortunately we are able to make out a good deal more about the strategy than about the tactics of Alfred’s campaigns. His itineraries are generally preserved, and the natural features of hill and vale and marsh and wood can easily be ascertained. Similarly there is a certain amount to be recovered concerning his work as a military organiser, though here our authorities give us hints rather than facts, and make it very hard to disentangle his reforms from those of his worthy successor, Edward the Elder. When Alfred first looked upon the face of war, the English had been already engaged for some seventy years in their great struggle to drive off the Vikings, and were prospering little in the attempt. The period during which the invaders had contented themselves with sporadic descents on the towns and monasteries hard by the sea, was long over. They were now cutting their way deep into England from every side, and prolonging their stay more and more every year. While Alfred was still a child by his mother’s knee, a yet more threatening stage had been reached: instead of returning to their homes by the Danish and Norwegian fiords, when autumn drew to an end, the enemy had begun to fortify some ness or island by the English shore, and to abide there all the winter months. The period of objectless plunder was drawing near its end, and that of settlement and conquest was approaching. It is not hard to make out the main causes of the ineffectiveness of the resistance which the English kingdoms offered to the invader; they were much the same as those which were to be seen in the Frankish empire on the other side of the British Channel—the want of any central organisation for combined defence—the want of any large bodies of professional fighting-men, fully equipped with the best arms of the day—the scarcity of fortified places—the non-existence of a war-fleet. In respect of the first of these matters the English were in some ways more unfortunate, in others happier, than the Franks. On the Continent the Vikings were confronted by a vast empire which was beginning to drop to pieces from its own weight; the realm of Charlemagne would have split up into national kingdoms even if there had been no invaders from outside to hasten the process. Particularism and heritage-partition were the order of the day; it was impossible to hope that the numerous descendants of the great Carling house would loyally aid each other against the external enemy, or that their heterogeneous subjects would care much for the woes of their neighbours. In England, on the other hand, the national evolution of the times was tending towards union. Even before the effects of the Danish invasions began to be felt, the states of the Heptarchy were already beginning to draw together into larger units. Offa the Mercian (755-794) had been suzerain of all England in a far truer sense than any of the early “Bretwalda” kings that were before him.