With exclusive rights over the sale of slaves in that part of Africa, De Souza soon amassed a fortune, and the slave market, situated near his house, became a hub for foreign and local buyers.
Saanud orjadega kauplemise eriõigused selles Aafrika osas, ajas de Souza peagi kokku suure varanduse ning tema elupaiga lähistel paiknevast orjaturust sai tõmbenumber nii välismaistele kui kohalikele kaupmeestele.