While most scholars of criminalized governance in Rio de Janeiro attribute its origins to the prison-based factions which formed during the military dictatorship (1964–85), this chapter argues that these arrangements emerged before, in the homes and on the streets and alleyways of the city’s favelas and housing projects. This chapter investigates these origins by focusing on the first embryonic gangs in Complexo da Maré in the 1970s. Combining archival research with oral histories of longtime residents, the chapter documents the emergence of Maré’s gangs after a variety of other non-state actors that had previously provided governance were increasingly marginalized during Brazil’s military dictatorship and as the abusive practices of police became more widespread. Maré’s incipient gang networks quickly began to compete over valuable drug-selling turf and, as the more successful ones consolidated territorial control, they expanded their organizations and governance activities. The chapter concludes with a description of the history of Rio’s prison-based factions and the marriage between these two organizational forms as the favela-based gangs integrated into these citywide networks.