History -- History 19 Islamic Empire -- 15 Islam -- 12 Caliphs 7 Biography 5 Caliphs -- 5 more ... Arabic language -- 4 Islam 4 Study and teaching 4 Abbasids 3 Logic -- 3 Religious aspects -- 3 Arabs -- 2 Criticism -- 2 Doctrines 2 History and criticism 2 Islamic Empire 2 Mahdi 2 Mahdism 2 Politics and government -- 2 Relations -- 2 Sudan -- 2 Translating 2 Translating and interpreting -- 2 Umayyad dynasty 2 622-661 1 Acquisition -- 1 Africa, North -- 1 Aghlabids 1 less ...