slew; at others, when hard pressed, they had simply to retire into these fens to be unapproachable. None among the Norman conquerors of other parts of the land could cope with Hereward, and at last William, in the summer of 1071, found it necessary to take the field in person against this own brother to Will-o'-the-Wisp. His plan of campaign was to attempt the invasion of the Isle of Ely simultaneously from two different points; from Brandon on the north-east, and from Cottenham on the south-west. The Brandon attempt was by boat, and soon failed: the advance from Cottenham was a longer business. Why he did not advance by that old Roman road, the Akeman Street, cannot now be explained. That splendid example of a causeway built across the morasses must still have afforded the better way, even though the Romans who made it had been gone six hundred years. But the Conqueror chose to advance from Cambridge by way of Impington, Histon, and Cottenham. It is, of course, possible that the defenders of the Isle had destroyed a portion of the old road, or in some way rendered it impracticable. His line of march can be traced even to this day. Leaving the old coaching road here at Cottenham Corner, we make for that village, famed in these days for its cream cheeses and grown to the proportions of a small town.[1] It was here, at Cottenham and at Rampton, that William collected his invading force and amassed the great stores of materials necessary for overcoming the great difficulty of entering the Isle of Ely, then an isle in the most baulking and inconvenient sense to an invader. Before the Isle could be entered by an army, it was necessary to build a causeway across the two miles' breadth of marshes that spread out from the Ouse at Aldreth, and this work had to be carried out in the face of a vigorous opposition from Hereward and his allies. It was two years before this causeway could be completed. Who shall say what strenuous labour went to the making of this road across the reedy bogs; what vast accumulations of reeds and brushwood, felled trees and earth? The place has an absorbing interest, but to explore it thoroughly requires no little determination, for the road that William made has every appearance of being left just as it was when he had done with it, more than eight hundred years ago, and the way from Rampton, in its deep mud, unfathomable ruts and grassy hollows, soddened for lack of draining, is a terrible damper of curiosity. The explorer's troubles begin immediately he has left the village of Rampton. Turning to the right, he is instantly plunged into the fearful mud of a mile-long drove described on the large-scale Ordnance maps as "Cow Lane," a dismal _malebolge_ of black greasy mud that only cattle can walk without difficulty. The unfortunate cyclist who adventures this way and pushes on, thinking these conditions will improve as he goes, is to be pitied, for, instead of improving, they go from bad to worse. The mud