"Our next move was to Saudi Arabia, where the Arab ethnicity with which I identified so strongly was suddenly cast into doubt: now it was my turn to be the "slave". My belief that I was an Arab, racially superior to non-Arab Africans, became laughable in the heartland of Arabia - a place where "Arabness" was not only determined by skin colour but by whether you could uninterruptedly trace your lineage back to the founding father of your clan. In fact, ancestry is so important in Saudi Arabia that courts have the power to annul a marriage if gaps are later discovered in a person's lineage, opening up the possibility of blood line pollution." (thanks Nouri)