On his first voyage (1482-3), he discovered the Congo River, and contacted the Bakongo? kingdom further upstream. He followed the African coast southward until Cape St. Mary in Angola.
On his second voyage (1485-6), he reached even further south, to Cape Cross in Namibia. He also sailed a short way up the Congo. It is not known whether he returned from this voyage.
[Diogo Cão] (external link)