The Muslim trade cities in Africa were connected to the ancient trade routes (or Silk Road as it was called in antiquity), by the Mediterranean Sea and the Black Sea in the North or the Red Sea and the Arabian Sea in the south. The Silk Road was the largest trade network of ancient times.
First thing that comes to mind is maybe withdrawing too much money (overdraft fee).
In the Scopes "Monkey trial" in 1925, a substitute school teacher was accused
by the state of Tennessee of violating the state law that made it illegal to teach
human evolution in any state funded school.
Scopes wasn't even sure whether he had ever actually
taught evolution, but he
said that he did, so that the case
could come to trial and be heard.