The lack of uniformity sets up Chapter 5, which focuses on the places that were developing along the main course of the Amazon and the lower parts of its tributaries. Most of these settlements were missions, and by the early eighteenth century they had taken on board a dual identity of being connected to the hinterland and to the colonial centre of Belém. This chapter seeks to show the riverine areas were not emptied, as many scholars have wrongly assumed. A more nuanced historical understanding of the ethnic profiles between missions and the hinterlands is revealed, where the core elements of each place include ethnic composition, its location (chosen or imposed), economic contribution to the colonial economy, military and missionary presence, and relationship to hinterland. We thus have the three spaces emerging by the mid eighteenth century – the Amerindian complexes in the hinterland, the colonial sphere centred on Belém, and the riverine settlements which formed their own assemblies.