[1] His business was a "highly organized mercantile house capable of operating on four continents" and may have had up to 50 employees.
[4] According to a British report based on a declaration by Da Fonseca, his profits in 1844 were £150,000.
[4] He trafficked enslaved people from Angola and the coast near the Congo River.
[2] In 1844 or 1845, Da Fonseca bought the slaving brig Uncas from Cuban shippers who had in turn bought it from American slave trader William H. Williams of Washington, D.C.[5] Porpoise and Kentucky were also Da Fonseca's ships.
[6] Da Fonseca's major competitors in Brazil were José Bernardino de Sá and Tomás da Costa Ramos; all three hired U.S.-flagged ships and American captains and sailors during what was known as the "contraband era".