The earliest era in Egyptian history is called the Predynastic period. The neolithic ended in Egypt around 4400 BCE with the appearance of the Amratian culture in Upper Egypt. The Amratians buried their dead in communal cemeteries in the desert, and showed signs of caring about the fate of the dead by such actions as covering the bodies with mats. In Lower Egypt, the Maadi culture developed around 4000 CE, about the same time that the Amratians underwent significant changes, evolving into or being replaced by the Gerzean culture. The Gerzeans continued to bury their dead in the desert, while the Maadi placed their dead in burial mounds. All three cultures produced distinctive pottery, which has helped Egyptologists to identify where and when each culture was active. Around 3200 BCE, a group from Upper Egypt came to dominate the whole country, which Egyptologists designate as Dynasty 0. The burial of the Dynasty 0 ruler King Scorpion shows signs of the formation of Pharaonic civilization. Tags that served as an inventory of King Scorpion's funerary goods are the earliest known example of a writing system.