Egypt has a history almost older than any other civilization on Earth, a history that stretches back many thousands of years. Evidence of human existence around the Nile dates back to at least the Paleolithic era, over 12,000 years ago. Civilization there started to develop when small tribes of hunter-gatherers and fisherman settled there, and a culture began to form. From there, the population living by the Nile thrived, as the yearly flooding of the nile brought incredibly rich soil for farming, and by 6000 BC, advanced agricultural practices had developed, as did large-scale building construction. Three thousand years later, Egypt was united from many petty rulers and established as a kingdom. Traditionally this feat is attributed to King Menes, also known as Narmer, though the process was apparently long drawn out. Menes is said to have been the first king in a lineage of dynasties that would rule Egypt for the following three thousand years. During this time of unification under a sovereign ruler, Egypt's thriving increased exponentially, and a deeper culture formed; Egyptian religion, art practices, language, customs, and quality of living became richer and more advanced. They developed heiroglyphics, a more complex pantheon of gods, and extensive class system of living, with peasants, merchants, priests, and nobles, among other groups.By the time of the eighteenth dynasty, around 1500 BC, Egypt had risen to become an international power, solidifying its power on a regional scale, and conquering many enemy neighboring countries.