Ancient Egyptian civilization, arising in the Nile River valley, benefited from the steady, regular Nile floods which provided a consistent, predictable food source. Egyptian society went through periods of unity and disunity (known as “Kingdoms” to historians) over its long history.

By Jeff Dahl [GFDL (http://www.gnu.org/copyleft/fdl.html) or CC-BY-SA-3.0-2.5-2.0-1.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons
Below are two examples of written sources from Old and New Kingdom Egypt.
The Precepts of Ptah-Hotep
The Victory of Ramses II Over the Khita