The Formative Stage or "Neo-Indian period" is a theoretical archaeological term applied to North and Meso-American societies that existed between 1000 BCE and 500 CE. It is the third of five stages defined by Gordon Willey and Philip Phillips' 1958 book Method and Theory in American Archaeology.
Cultures of the Formative Stage are supposed to possess the technologies of pottery, weaving, and developed food production. Social organization is supposed to involve permanent towns and villages, as well as the first ceremonial centers. Ideologically, an early priestly class or theocracy is often present or in development.