The history of Egypt can be traced back from 4,400 years before the Christian era, and is divided into thirty Dynasties, whose succession was the result of failure in any of the original lines of marriage, or marriage with a female of lower rank, or of a revolution. The thirty Dynasties are divided into three groups:— Dynasties   I.-XI. (B.C. 4400-2466) The Ancient Empire.    ”   XII.-XIX. (B.C. 2466-1200) The Middle Empire.    ”   XX.-XXX. (B.C. 1200-340) The New Empire. These dates and arrangements are formulated chiefly on the basis of a work written in Greek, and compiled by Manetho, an Egyptian priest who lived in the third century B.C. The kings of Egypt have been named Pharaohs from the title “Peraa”—"great house." The seat or centre of the government shifted its position according to dynastic reasons, or from policy. During the ancient empire it was first at Memphis, and then moved to Abydos and other places in the south as the empire extended. When Egypt was in the height of its glory the centre of government was chiefly at Thebes, but moving often according to revolution or foreign oppression. Rameses and his near successors held their court at the northern city of San, or Tanis. The time of the New Empire was chiefly a period of foreign rule and slow decadence, the seat of the empire shifted to nearly all the former places or capitals and to Bubastis or Sais with each political change. [Illustration: Fig. 87.—The Great Pyramid of Kheops, and Small Pyramids; from Perring. (P. & C.)] Menes was the first historical king of Egypt, and was supposed to have founded Memphis, where the worship of the god Ptah, “Creator of gods and men,” was first instituted, as well as that of Apis or Hapi, the sacred bull—the Serapis of the Greeks. For the next six hundred years we know scarcely anything of Egyptian history except the names of the kings, until we come to the great period of the Fourth Dynasty (B.C. 3766-3566). Seneferu was the founder of this Dynasty. He conquered the peninsula of Sinai, and worked the valuable mines of copper and turquoise found in that country. His son and successor, Khufu, better known as Kheops (B.C. 3733-3700), was the builder of the Great Pyramid at Gizeh (Fig. 87), which he erected for his tomb. The king Kha-f-Rā (Kephren) (B.C. 3666-3600), built the Second Pyramid, and his son, Men-kau-Rā (Mykerinos) was the builder of the Third Pyramid. Men-kau-Rā was a wise and humane sovereign, and it is recorded to his honour, as an exceptional qualification, that “he did not oppress his people.” In this he was different to most of the Pharaohs. His mummified remains are now in the British Museum. The Sphinx, or man-headed lion, carved out of the solid rock, is near the Great Pyramid, and is supposed to be the work of a much earlier period (Fig. 91). [Illustration: Fig. 88.—Section through the Great Pyramid of Kheops. (P. & C.)]