We have next to consider what happened after the great gap in Egyptian history between the sixth and twelfth dynasties, 3500 B.C.--2851 B.C. (Mariette); from Nitocris to Amenemhāt I. We pass to the Middle Empire, and here we have merely to deal with the worships previously referred to in Northern Egypt. Amenemhāt I. built no pyramids, he added no embellishments to Memphis; but he took Annu under his care, and now we first hear of Thebes.[109] Usertsen I. built no pyramids, he added no embellishments to Memphis, but he also took Annu under his care, and added obelisks to the temples, one of which remains to this day. Further, he restored the temple of Osiris at Abydos, and added to the temple of Amen-Rā at Thebes.[110] Surely it is very noteworthy that the first thing the kings of the twelfth dynasty did was to look after the only three temples in Egypt of which traces exist, which I have shown to have been oriented to the Sun _not_ at an equinox. It is right, however, to remark that there seems to have been a mild recrudescence of pyramid building towards the end of the twelfth dynasty, and immediately preceding the Hyksos period, whether as a precursor of that period or not. Usertsen's views about his last home have come down to us in a writing by his scribe Mirri:--[111] "Mon maître m'envoya en mission pour lui préparer une grande demeure éternelle. Les couloirs et la chambre intérieure étaient en maçonnerie, et renouvelaient les merveilles de construction des dieux. Il y eut en elle des colonnes sculptées, belles comme le ciel, un bassin creusé qui communiquait avec le Nil, des portes, des obélisques, une façade en pierre de Rouou." There was nothing pyramidal about this idea, but one hundred and fifty years later we find Amenemhāt III. returning both to the gigantic irrigation works and the pyramid building of the earlier dynasties. The scene of these labours was the Fayyûm, where, to crown the new work, two ornamental pyramids were built, surmounted by statues, and finally the king himself was buried in a pyramid near the Labyrinth. _The Buildings of the Eighteenth Dynasty._ The blank in Egyptian history between the twelfth and eighteenth dynasties is known to have been associated with the intrusion of the so-called Hyksos. It is supposed these made their way into Egypt from the countries in and to the west of Mesopotamia; it is known that they settled in the cities with east and west walls. They were finally driven out by Aāhmes, the king of solstitial-solar Thebes, who began the eighteenth dynasty. On page 338 I have shown what happened after the first great break in Egyptian history--a resuscitation of the solar worship at Annu, Abydos and Thebes. I have next to show that precisely the same thing happened after the Hyksos period (Dyn. 13 (?) Mariette, 2233 Brugsch; Dyn. 18, 1703 B.C., Mariette, 1700 B.C. Brugsch) had disturbed history for some five hundred years.