Egypt was probably never more prosperous, nor her people happier, than during the centuries in which the Amenemhats and Usertesens ruled the land. The only reign in which serious warfare occurred was that of Usertesen III. He determined to acquire for Egypt the disputed territory in the south—_Ta-Khent_ (Nubia)—and, with it, its golden treasures. But he did not succeed in finally conquering and driving back the dark-hued tribes until after a very fierce and protracted struggle. He erected fortresses on the southern frontier, and an inscription on the rock proclaimed: ‘This is the southern boundary, fixed in the eighth year of King Usertesen III. No negro shall be permitted to pass it except for the purpose of bringing vessels laden with their asses, camels, and goats, or of trading by barter in Ta-Khent. To such negroes, on the contrary, every favour shall be shown.’ [Illustration: Vincent Brooks-Day & Son, Lith. BOATMEN AND CATTLE DRIVERS.] If Usertesen III. secured one new province for Egypt by the ruthless force of war, his successor, Amenemhat III., won another by gentler means. Egypt is, no doubt, what Herodotus called it, the ‘gift’ of the Nile. But for the Nile the burning wastes of Sahara would stretch eastwards without interruption to the Red Sea. By means of the great river and its yearly inundation, the long narrow valley between the Libyan and the Arabian mountains is watered and richly fertilised for the space of several miles; where the inundation ceases the desert sand begins. This long strip of fertile country, together with the Delta into which it expands, constituted Egypt;[24] _Khemi_ (the black country), its people called it from the dark colour of its rich soil, which rewarded the husbandman’s toil with two or three crops a year—crops of a luxuriance difficult for us to realise. The name of Egypt was a synonym for rich fertility: ‘Well watered everywhere,’ we read in Genesis, ‘like the garden of the Lord, like the land of Egypt.’ In the days when the twelfth dynasty ruled, _i.e._ probably more than 2000 B.C., the average rise of the Nile was more than twenty feet higher than it is at the present day. At the point where Usertesen III. had erected his frontier fortress, the height attained by the river during many successive inundations is recorded. His successor, Amenemhat III., not only carefully noted the annual rise, but turned his attention to the great work of controlling the overflow, for the country was liable to suffer severely in case either of an excess or a deficiency.