Mariette, who is the best and latest authority, and who has done so much to discover monuments of the earlier dynasties, concludes, as the result of a careful revision of Manetho's lists, and of the authentic records from temples, tombs, and papyri, that 5004 B.C. is the most probable date for the accession of Menes, and this date is generally adopted by modern Egyptologists. Some make it rather longer, as Boeck 5702 B.C., and Unger 5613 B.C.; while others make it a little shorter, as Maspero 4500 B.C., and Brugsch[1] 4455; but it is to be observed that the date has always lengthened with the progress of discovery. Thus the earlier Egyptologists such as Wilkinson, Birch, and Poole assigned a date not exceeding 3000 B.C. for the accession of Menes; twenty years later Bunsen and Lepsius gave respectively 3623 and 3892 B.C.; and since the latest discoveries, no competent scholar assigns a lower date than 4500 B.C., while some go up to 5702 B.C., and that most generally accepted is 5004 B.C. It is safe to conclude, therefore, that about 5000 B.C., or very nearly 7000 years before the present time, may be taken provisionally as the date of the commencement of authentic Egyptian history, and that if this date be corrected by future discoveries it is more likely to be increased than diminished. [1] Brugsch, however, confines himself mainly to kings whose names are confirmed by monuments, and takes no account of the numerous names of unknown kings in royal genealogies, of which no confirmation has yet been found, so that practically his estimate is not inconsistent with that of Mariette. This immensely long period of Egyptian history is divided into three stages--the Old, the Middle, and the New Empires. The Old Empire began with Menes, and lasted without interruption for about 1500 years, under six dynasties of kings, who ruled over the whole of Egypt. It was a period of peace, prosperity, and progress, during which the pyramids, the greatest of all human works, were built, literature flourished, and the industrial and fine arts attained a high degree of perfection. At the very commencement of this period we find the first King Menes carrying out a great work of hydraulic engineering, by which the course of the Nile was diverted, and a site obtained on its western banks for the new capital of Memphis. His immediate successor is said to have written a celebrated treatise on Medicine, and the extremely life-like portrait-statues and wooden statuettes, which were never equalled in any subsequent stage of Egyptian art, date back to the fourth dynasty. [Illustration: PYRAMIDS OF GIZEH AND SPHYNX. (From Champollion's _Egypt_.)]