Mubarak was deeply disturbed by a black African holding high office.

Evidence

This apparent social upheaval upset `Alï Mubärak deeply. He turned to his father for answers about how a dark-skinned African could ever achieve so high a position. They mulled over it together: “This ma´mür is not a Turk, since he’s black,” I said. — Eve M. Troutt Powell, A Different Shade of Colonialism_…, 258