Four hundred years after Herodotus, Diodorus travelled to Egypt.[7] He tells that, according to some fabulous accounts, gods and heroes first ruled over Egypt for something less than 18,000 years. The last of these was Horus, the son of Isis. After these came 470 native kings, of whom the first was Menes, before the time of the Macedonian and Persian rule, and also four Ethiopian kings and five queens. The Ethiopians did not immediately succeed each other, but at intervals, and their united reigns amounted to a little less than thirty-six years. "Of all these kings the priests have sketches in their holy books, handed down through successive generations from extreme antiquity, showing how tall each king was, what he was like, and what he accomplished in his reign." If we place the reign of Menes 479 generations before Cambyses, this computation, on the reckoning of Herodotus, would place the accession of Menes in the year 16492 B.C.; taking a shorter average length for the generations, we may bring it to the year 12500 B.C. But Diodorus shows from other accounts that this mode of computation is inadmissible. He tells us that the priests of Egypt numbered about 23,000[8] years from the reign of Helius or Hephæstus, who, according to other priests, was the first of the gods to reign,[9] till the entrance of Alexander into Asia (334 B.C.). If of this total we allow about 18,000 years to the gods, the accession of Menes would have to be placed about the year 5300 B.C.[10] But as Diodorus also says that something less than 5,000 years had elapsed since the first human king to his arrival in Egypt, Menes' reign would fall about the year 5000 B.C. Diodorus fixes the accession of this king even more closely when he remarks, in a third passage, that the Egyptians assured him that, "for more than 4,700 years, kings, mostly natives, had ruled, and the land had prospered greatly under them."[11] With this agrees the further account given by Diodorus, that according to some the largest pyramid was built 3,400 years before his time. According to this Menes cannot be carried back further than 4,800 years B.C. If Menes founded the kingdom of Egypt 4,800 years B.C., it continued for 4,275 years under native kings; and if in this period 346 kings ascended the throne, as Herodotus says, or 479, as Diodorus, the average duration of each reign would be in the first case more than twelve years, in the second less than nine, which contradicts all credible history. The lowest average of oriental reigns is fifteen years.