This supremacy declined during the twenty-first and twenty-second dynasties, but, at the same time, Egyptian chronology becomes more certain as opportunities of comparison with the facts of Hebrew history increase. The date of 980, within a year or two, may be given with confidence as that of the accession of Sheshonk I., the contemporary of Solomon and Rehoboam. From that date onwards, the constant struggles between Egypt and its neighbours, especially with Assyria, multiply our opportunities for synchronic comparison. In the seventh century the country was opened to the Greeks, the real creators of history, who brought with them their inquiring spirit and their love for exactitude. After the accession of Psemethek I., the founder of the twenty-sixth dynasty, in 656, our historical materials are abundant. For that we must thank the Greek travellers who penetrated everywhere, taking notes which they afterwards amplified into narratives. It is a singular thing, that even as late as the Ptolemies, when the power of the Macedonian monarchy was fully developed, the Egyptians never seem to have felt the want of what we call an _era_, of some definite point from which they could measure the course of time and the progress of the centuries. "They were satisfied with calculating by the years of the reigning sovereign, and even those calculations had no certain point of departure. Sometimes they counted from the commencement of the year which had witnessed the death of his predecessor, sometimes from the day of his own coronation. The most careful calculations will therefore fail to enable modern science to restore to the Egyptians that which, in fact, they never possessed."[55] [55] MARIETTE, _Aperçu de l'Histoire d'Égypte_, p. 66. Even thus summarily stated, these historical indications are enough to show how little foundation there is for the opinion which was held by the ancient Greeks, and too long accepted by modern historians. It was, they said, from Ethiopia that Egyptian civilization had come. A colony of Ethiopian priests from the island of Meroè in Upper Nubia, had introduced their religion, their written characters, their art and their civil institutions into the country. The exact opposite of this is the truth. "It was the Egyptians who advanced up the banks of the Nile to found cities, fortresses, and temples in Ethiopia; it was the Egyptians who carried their civilization into the midst of savage negro tribes. The error was caused by the fact that at one epoch in the history of Egypt the Ethiopians played an important part.