AD 900. This culture eventually extended as far west as Oklahoma, as far north as the present-day suburbs of Saint Louis, Missouri, in southwestern Illinois, and ranging east into the Southeastern Woodlands, to present-day North Carolina and as far south as present-day Mississippi. Site development and decline The people of the Middle Mississippian culture built and lived in a community (in what became southwestern Indiana around AD 1100 and remained there until AD 1450, a period that Marjory Honerkamp defined in the 1970s as the Angel phase. The Angel phase and the Mississippian culture town are named after the Angel family, who in 1852 began purchasing farmland that included the archaeological site. Archeologist Sherri Hilgeman and others have used the distinctive pottery produced at the Angel site and in other satellite communities in this section of the Ohio River valley to define the Angel phase as the middle period between the Emergent Mississippian Yankeetown phase (AD 750 to AD 1000) and the Terminal Mississippian Caborn-Wellborn phase (AD 1400 to AD 1700). The Angel chiefdom (a simple hierarchy led by a chief) was the regional trading center in a group of communities within of the Ohio River valley; it extended as far as the Green River in present-day Kentucky. The large residential and agricultural community was also the political, cultural, and economic center of the chiefdom, whose residents traded with other chiefdoms and peoples along the Ohio and Mississippi rivers. The Angel community primarily inhabited an area bounded by the Ohio River to the south, the White River and its East Fork to the north, the Wabash River to the west, and the Anderson River to the east. Archaeologists have inferred that the smaller communities (villages, hamlets, farmsteads and camp sites) were politically subordinate to the main Angel site. Continuing excavations at the site have revealed new elements of the complex society. Laborers built the main Angel site sometime after AD 1000. They also established the surrounding villages and farming areas along the Ohio River and engaged in hunting and farming on the rich bottom lands. In addition, the Mississippian culture is known for its earthen mounds, designed in shapes including platform, conical, and ridgetop (as also seen at the largest center, Cahokia in present-day southern Illinois). Working with a variety of soils to create a stable mass, the Mississippian people built major earthworks at the Angel site. The community eventually