The Tupi people, a subdivision of the Tupi-Guarani linguistic families, were one of the largest groups of indigenous peoples in Brazil before its colonization. Scholars believe that while they first settled in the Amazon rainforest, from about 2,900 years ago the Tupi started to migrate southward and gradually occupied the Atlantic coast of Southeast Brazil.
Many Tupi people today are merged with the Guaraní people, forming the Tupi–Guarani languages. Guarani languages are linguistically different from the Tupian languages.
The Tupi people inhabited 3/4 of all of Brazil's coast when the Portuguese first arrived there. In 1500, their population was estimated at 1 million people, nearly equal to the population of Portugal at the time. They were divided into tribes, each tribe numbering from 300 to 2,000 people. Some examples of these tribes are: Tupiniquim, Tupinambá, Potiguara, Tabajara, Caetés, Temiminó, Tamoios. The Tupi were adept agriculturalists; they grew cassava, corn, sweet potatoes, beans, peanuts, tobacco, squash, cotton and many others. There was not a unified Tupi identity despite the fact that they spoke a common language.
Upon discovering the existence of the Tupi people, it was assumed by Portuguese settlers that they lacked any sort of religion, a belief that began the process of assimilating the Tupi to Christianity. The settlers began erecting villages for the Tupi, known as aldeias, with the intention of more disciplined religious conversion and institutionalization of European customs. Aside from being assimilated, the Tupi were found to be of use to the Portuguese, who required laborers for cultivating and shipping their exports. This use in harvesting resources led to their eventual enslavement and in turn, the spread of fatal European diseases on the plantations they worked at. This combination of factors nearly led to their complete annihilation, with the exception of a few isolated communities. The remnants of these tribes are today confined to indigenous territories or acculturated to some degree into the dominant society.