In the chapter The Land of Shadow in The Return of the King the narrator says: "Neither he nor Frodo knew anything of the great slave-worked fields away south

In the chapter The Land of Shadow in The Return of the King the narrator says: "Neither he nor Frodo knew anything of the great slave-worked fields away south in this wide realm, beyond the fumes of the Mountain by the dark sad waters of Lake Núrnen; nor of the great roads that ran away east and south to tributary lands, from which the soldiers of the Tower brought long waggon-trains of goods and booty and fresh slaves. Here in the northward regions were the mines and forges, and the musterings of long-planned war; and here the Dark Power, moving its armies like pieces on the board was gathering them together."