William Muir,
The Caliphate: Its Rise, Decline and Fall…
“ But neither here nor elsewhere did they intermarry with the Arabs on equal terms, nor were they, in point of fact, looked upon otherwise than as of inferior caste. Thus though in theory, on becoming Muslims, conquered nations might enter the "equal brotherhood" of Islam, they formed not the less an altogether lower estate. The race and language, ancestral dignity, and political privileges of the Arab hue continued for many generations to be paramount. ”
