Question

Which of these longstanding african developments ended in the 1500s?

Answer 1

Islam continues to grow in Africa to this day.  Christian mission work continues in Africa too.  And farming continues to expand.

The Bantu migrations ended in the 1500s.  Bantu-speaking peoples migrated from Western Africa (in the area of modern Nigeria) throughout southern parts of Africa starting around 1000 BC and continuing to the 1500s (or perhaps a bit later, by some accounts).