The civilization if ancient Egypt developed over more than three millennia. It begtan with the political unification of the major Nile Valley cultures under one ruler, the first pharaoh (3150 BC), and led to a series of golden ages known as Kingdoms. The Kingdoms were separated by periods of relative instability known as Intermediate Periods. After the end of the loast golden age, the civilization of ancient Egypt entered a period of slow, steady decline when Egypt was conquered by a succession of foreign adversaries. The power of the pharaohs officially ended in 31 BC, when the early Roman Empire conquered Egypt and made it a province of the Empire.