History -- 52 Caliphs 11 History 11 Islamic Empire -- 7 Islam 4 Caliphate 3 Islam -- 3 more ... Biography -- 2 Caliphs -- 2 Islam and politics -- 2 Leadership -- 2 Politics and government 2 Religious aspects -- 2 Riddah Wars 2 Siffin, Battle of, Syria, 657 2 Abbasids 1 Apostasy -- 1 Arabs -- 1 Biography 1 Caliphate -- 1 Camel, Battle of the, Iraq, 656 1 Circassians -- 1 Conduct of life 1 Economic consitions 1 Historiography -- 1 History, Military 1 Imams (Shiites) 1 Industries -- 1 Islam and state -- 1 Islamic civilization 1 less ...