In Roman army there were black people

In this years the racism is growing up again, so I would like to be clear about this:
in the roman army there were black people. It makes sense if you think about how big was the Roman Empire and about how many different people there were under it. Roman civilization was very inclusive and tolerant, so, why should not be black people in it? In fact, we know that at last 3 emperors were born in Africa: Settimio Severo, Gordiano I and Gordiano II.
But let's listen the historicians; Mary Beard, classicist and Professor of University of Cambridge confirm and support this theory.
So, don't pay attention to who says that the civilizing society of the ancient world was made only by white people.