This is the beginning of the famous bas relief at Persepolis in Iran that depicts people of all the nationalities under Persian rule bearing tribute to the king.

I'm able to identify this person as an Ethiopian because, when I went to Ethiopia in 2007, I learned that Ethiopians were depicted in sculpture at Persepolis, and because our guide identified this group as representing Ethiopians.

According to Donald N. Wilber's book Persepolis, The Archaeology of Parsa, Seat of the Persian Kings, this group "shows the Kushia (Ethiopians), with one member carrying a vase and another bearing an elephant tusk over one shoulder and leading an okapi."

In a footnote, Wilber adds that "Herodotus wrote that each third year the Ethiopians brought two quarts of virgin gold, five boys, and 20 elephant tusks."