It's old. At least dating back to Norman times, that is eleventh century. At that time Hereward The Wake led his loyal band of fenmen in a guerrilla war against William and his occupying troops. Because of his knowledge of the waterways and marshes Hereward led William a merry dance. The Normans built a causeway, which may or may not be Aldreth Causeway, in order to invade the Isle of Ely which was at that time surrounded by swampland. Legend has it that the causeway sank under the weight of the troops and many of the Norman soldiers met a watery and untimely end.