In March 1883 Wissmann gave the name "Zappo Zap" to a Songye leader known as Nsapu Nsapu who ruled over the town of Mpengie, part of the Ben'Eki kingdom in the eastern Kasai region.
On his way to East Africa Wissmann hired a mercenary force of mostly Sudanese soldiers from decommissioned units of the Anglo-Egyptian army to whom later a number of Zulus from South Africa were added, all under the command of German officers.