From Dahshur down to Illahun and Hawara lie the pyramids of the great kings of the XIIth Dynasty, who, though Thebans, realised that the centre of gravity of the national government must be further north, and who therefore made their royal residence between Memphis and the Fayum. The earlier kings of the dynasty, Amenemhat I and Senusert I, had their pyramids at Lisht; Amenemhat II and Senusert III preferred Dahshur for their resting-place; while Senusert II chose Lahun, and Amenemhat III Hawara, where he could sleep beside the great works which he had wrought at Lake Moeris for the welfare of his land. The XIIth Dynasty pyramids are not imposing externally. The ruinous piles of brickwork at Dahshur and Lahun look more like gigantic ant-heaps than true pyramids; yet they were the work of kings who in their own way were quite as powerful as the pyramid-builders of the IVth Dynasty, and the detail of the inner workmanship of the sarcophagus chambers is quite as remarkable as anything to be seen at Gizeh. Part of the reason for the difference is a change, not so much in the ideal for which the pyramid was constructed (for that remained constant throughout the history of Egypt), but in the conception of the best means towards the realising of the ideal. “It seems,” says Petrie, describing the change which Senusert II introduced in his pyramid at Lahun, “that the pyramids of the earlier kings had fallen a prey to violence already, the signs of personal spite in the destructions are evident. Therefore Senusert II determined to abandon the old system of a north entrance in the face, and to conceal the access to the interior by a new method.” His method was to excavate his sarcophagus chamber entirely out of the solid rock on which the pyramid was founded, and to place the entrance to the passage which led to the chamber outside of the pyramid altogether. The shaft which gives access to the passage actually opens out on the plain, beneath the floor of the tomb of one of the princesses of the dynasty. Inside the rock-hewn chamber which was protected with such care, and which was splendidly lined with red granite, stood the red granite sarcophagus, “exquisitely wrought,” says Petrie, “the errors of flatness and straightness being matters of thousandths of an inch.”