It would seem that the Anglo-Saxon invasion of a great part of eastern Britain in the fifth century radiated fan-wise from the gateway of the Wash and of the Fenland Gulf. If this is true, it is not surprising. The position of the continental base of the Anglo-Saxons made the area a natural entry into the Midland plain; and the invaders, with the Wash behind them, gazed upon no unfamiliar scene. The region into which they came may not have been so different from their former homeland on the flats of northern Germany, the homeland which Bede tells us they had so completely deserted. They penetrated by way of the Fenland rivers, up the Nene, the Welland, the Ouse, and the Witham, and this big spread was supplemented to the north and to the south by the smaller river entrances, the Bure, the Yare, the Waveney, the Humber and so on. The archaeological finds, as plotted by Mr Thurlow Leeds, are located along the courses of navigable streams and their tributaries, and are disposed concentrically around the Fenland. Dr Cyril Fox has moreover indicated affinities, during the earlier Saxon period, between the opposite shores of this marshy gulf. All had changed, however, when the tribes emerged into the light of history. The Fenland basin, characterized at an earlier epoch by a certain cultural unity, had now become a frontier region, separating peoples and exercising a repelling action revealed in the making of the Anglo-Saxon States. Kingdoms, finding their limits here, partitioned the marshy wastes between them, and the barrier of the Fens became a permanent feature in the political geography of the Anglo-Saxon Heptarchy.