The year: 1581. The place: feudal Japan, Kyoto.

The person: Yasuke. A six-foot-tall African man kidnapped as a boy, possibly from either Mozambique, South Sudan, Nigeria, or Ethiopia (there’s little surviving documentation) who by 1581 was accompanying Jesuit missionary Alessandro Valignano, dispatched by Pope Gregory XIII to inspect new Roman Catholic missions in Asia, as an attendant bodyguard.

After two years of inspecting Jesuit missions, Alessandro prepared to leave but requi...