The explorer most often cited in this respect is the fourteenth century ruler Abu Bakr II, the mansa of Mali, who according to an Egyptian chronicler abdicated his throne because he "did not believe that it was impossible to reach the extremity of the ocean that encircles the earth, and wanted to reach that [extremity]." According to the same source, Abu Bakr equipped a fleet of 200 ships and sailed off into the Atlantic, leaving his throne to Mansa Musa, who became the best-known of the rulers of that empire, and who supposedly discussed the expedition while in Egypt on his well-known hajj.

The outcomes of the expedition, which never returned, including speculation that the fleet had discovered the Americas, were discussed here in the thread

Abu Bakr II set sail on a expedition from Mali. Is there any evidence of what happened to his fleet?

with u/Commustar.