The Mississippian stage is usually divided into three or more periods. Each of these periods is an arbitrary historical distinction that varies from region to region. At one site, each period may be considered to begin earlier or later, depending on the speed of adoption or development of given Mississippian traits.Early Mississippian cultures are those which had just made the transition from the Late Woodland period way of life (500-1000 A.D.). Different groups abandoned tribal lifeways for increasing complexity, sedentism, centralization, and agriculture. The Early Mississippian period is considered to be, in most places, c. 1000-1200 A.D.The Middle Mississippian period is often considered the high point of the Mississippian era. The formation of complex chiefdoms besides Cahokia, and the spread and development of the SECC art and symbolism are characteristic changes of this period. The Mississippian traits listed above came to be widespread throughout the region. In most places, this period is recognized as occurring c. 1200-1400 A.D.The Late Mississippian period, usually considered from c. 1400 to European contact, is characterized by increasing warfare, political turmoil, and population movement. The population of Cahokia dispersed early in this period (1350-1400), perhaps migrating to other rising political centers. More defensive structures are often seen at sites, and sometimes a decline in mound-building and ceremonialism. Although some areas continued an essentially Middle Mississippian culture until the first significant contact with Europeans, most areas had dispersed or were experiencing severe social stress by 1500.