About 5,500 years ago, four of the world's most prestigious ancient river civilizations arose. Our world stood amazed and awed, wondering how these civilizations developed. Egypt and Mesopotamia were the first ancient river civilizations to create cities and their own ways of life. Society, geography and religion played a huge role in the development of ancient cities. Although there is evidence of early Sumerian contact with the Egyptians, Egyptian civilization was largely self-generated and its history and cultural patterns differed from those of Mesopotamia. The Early Dynastic Period was the era of Egypt's initial unification and state-building under the guidance of its first three royal dynasties. Between 2660 and 2180 BC. BC, the fundamental characteristics of Egyptian cultures appeared. Egypt was one kingdom and it was divided into provinces, or provincial names. The kingdom was ruled by a pharaoh, who was not only a king but was also considered a god. The provinces were governed by nomarchs better known as provincial governors. The Egyptians were divided into classes: upper class, middle class and lower class. The pharaoh and his family were at the top of the Egyptian class system. People could move from one class to another depending on their situation. The Mesopotamian civilization exerted a profound cultural influence throughout Western Asia and beyond for approximately 3,000 years. Mesopotamia had many independent city-states with their own government and ruler. Priests ruled these city-states along with other administrators such as organizers and managers. Since unrest and tensions often arose between city-states, Mesopotamian political unification was rarely achieved. Mesopotamia was constantly being invaded by foreigners who would incorporate their culture into a new society and form a new one by force. Mesopotamian geography affected their society because Mesopotamia was located on an open plain with no protection from foreign intrusions. Egypt, on the other hand, was centered on the Nile and protected by natural borders. This allowed the kingdom of Egypt to prosper and last for thousands of years. Mesopotamia was not considered a nation or country, it was considered a region between the Tigris and Euphrates Rivers that established a number of highly organized city-states. Since each city-state was independent, Mesopotamia had no capital. Religion was very important to the ancient Egyptians who believed in many gods, which meant they were polytheists..