Evidentiality is prone to diffusion and has been identified as a diagnostic feature of linguistic areas such as the Vaupés region of the Brazilian Amazon (e.g., Aikhenvald and Dixon 1998). This paper examines the processes by which a complex evidentiality system can develop in a particular language, catalyzed by language contact but fed by language-internal resources. The discussion considers data from Hup, a Vaupés language of the Vaupés-Japurá (Makú) family, and demonstrates that Hup has developed an evidentiality system parallel to those found in the two other unrelated language families of the region. Finally, a reconstruction of an evidentiality distinction for the Vaupés-Japurá family challenges Aikhenvald and Dixon’s (1998) claim that evidentiality had two independent points of innovation in northern Amazonia.