That this had been the age-long course of the Fenland waters is shown by the existence of a huge Roman sea wall running round the old coast line from Lynn to Wisbech, and from Wisbech to Sutton in Lincolnshire. This wall traces for us the outline of a great tidal estuary running up to Wisbech, which continued an estuary even to the eighteenth century. But the diversion of the greater part of its river water to Lynn proved fatal to it. Such stream as was left, scarcely more than that of the Nene, could not, at the ebb, scour out the channel through the sands which the flood-tide continually tended to silt up. Wisbech became more and more shut off from the sea, and is now ten miles away from it. And further, the inability to escape quickly enough through these choking sands drove the river water at Wisbech back upon itself and forced it to "drown" the neighbouring fens; while at Lynn the same disastrous effect was produced by the new volume of water being too great for the narrow bed of the Little Ouse and flooding over the banks all round. The Marshland, as the Norfolk district protected by the Roman wall was called, suffered especially from this result of interfering with Nature. Nor did it prove possible to undo the mischief. When once a short cut has been made for a great river, it is no easy matter to turn the stream back into its old tortuous course; and, when once an estuary has got thoroughly silted up, it is yet more difficult to restore it to its old condition. Throughout the Middle Ages constant complaints were made, and occasional attempts; but these were always brought to nought by some conflicting interest or other which got the ear of the Government. The fen problem was early recognised as a matter of national concern, and, from the time of Edward the First onwards, the Crown tried to grapple with it, but by hopelessly futile methods. To begin with, the system of Local Government already established for the regulation of Romney Marsh in Kent was extended to the Fenland. The Sheriff was bound to summon twenty-four "jurats" from the inhabitants of the neighbourhood, to deal with each difficulty as it arose. But a plan which worked well enough for a district only some ten miles by fifteen, and with no river to speak of, was wholly inadequate to deal with the huge area and mighty forces of the Fenland, even when this was divided (as it still is for drainage purposes) into three "Levels," "North," "Middle," and "South." The jurats hated their invidious office, and were themselves hated by the inhabitants; each man always declaring that they had saddled him with repairs which ought to have been laid upon some neighbour, and each man ready to see his own land "drown" rather than put in a single spadeful of work which, in his view, should have been someone else's job.