The tidal river below Gainsborough passes on through scenery less and less interesting. After a time it ceases to divide the county of Nottingham from Lincoln, and is bordered on both banks by the latter. The district to the west is called the Island of Axholme. This, "though now containing some of the richest land perhaps in the kingdom, was formerly one continued fen, occasioned by the silt thrown up the Trent with the tides of the Humber. This, obstructing the free passage of the Dun and the Idle, forced back their waters over the circumjacent lands, so that the higher central parts formed an island, which appellation they still retain. From this circumstance it became a place so deplorable that Roger, Lord Mowbray, an eminent baron in the time of King Henry II., adhering to the interests of the younger Henry, who took up arms against his father, repaired with his retainers to this spot, fortified an old castle, and for some time set at defiance the king's forces who were sent to reduce him to obedience."[4] The authority just quoted tells us that an attempt to regulate the drainage of Axholme was made so long since as the reign of Henry V. by one of the Abbots of Selby, who constructed "a long sluice of wood" upon the Trent "at the head of a certain sewer called the Maredyke," and this he did "of his free goodwill and charity for the care of the country." This was destroyed of malicious purpose in the days of his successor, who rebuilt the same of stone. But the chief reclamation of land, not only in the marshes of Axholme, but also in the adjacent fens called Dikes Mersh and Hatfield Chase, in the county of York, was undertaken in the earlier part of the reign of Charles I., when a contract bearing date May 24, 1646, was made with Cornelius Vermuden, which was successfully carried out during the next five years, so that many thousand acres of land were made available for agricultural purposes--"the waters which usually overflowed the whole level being conveyed into the river Trent, through Snow sewer and Althorpe river by a sluice, which opened out the drained water at every ebb, and kept back the tides upon all comings-in thereof."