Account of the discovery (1980) and archaeological excavation of a black American cemetery closed in 1841 (First African Baptist Church Cemetery) of a non-slave community in Philadelphia (current city center) very little documented in the archives and of which all physical trace had been lost for a century. Observation of the stages of the excavation, of the analysis of the bones in the laboratory and of what these burials were able to reveal about the demography of the time, of the survival of Africanisms, etc.