The history of Egypt is the longest continuous history, as a unified state, of any country in the world. The Nile valley forms a natural geographic and economic unit, being bounded to the east and west by deserts, to the north by the sea and to the south by the Cataracts of the Nile. The need to have a single authority to manage the waters of the Nile led to the creation of the world's first state in Egypt in about 3000 BC. Egypt's peculiar geography made it a difficult country to attack, which is why Pharaonic Egypt was for so long an independent and self-contained state. Once Egypt did succumb to foreign rule; however, it proved unable to escape from it, and for 2,300 years Egypt was governed by foreigners: Persians, Greeks, Romans, Byzantines, Arabs, Turks and British. When President Nasser (President 1954-1970) once said that he was the first native Egyptian to exercise sovereign power in Egypt since the last Pharaoh, Nectanebo II, who was deposed by the Persians in 343 BC, he was only slightly exaggerating.
Egyptian history has been divided by this encyclopedia into six periods: