Their father , Caliph Harun al-Rashid , had named Name_conferral al-Amin as the first successor , but had also named Name_conferral al-Ma'mun as the second , with Khurasan granted Giving to him as an appanage .

The city fell after a year , al-Amin was executed Killing , and al-Ma'mun became Becoming Caliph .

Consequently , al-Ma'mun 's uncle Ibrahim was proclaimed Statement rival Caliph at Baghdad in 817 , forcing Request al-Ma'mun to intervene Response personally .

On 3 March 1924 , the Ottoman caliphate was officially abolished and the last Caliph was exiled .

The Abbasid campaign was led Causation personally by the Caliph al-Mu'tasim ( reigned 833–842 ) , in retaliation Revenge to a virtually unopposed expedition launched Motion by the Byzantine emperor Theophilos ( r. 829–842 ) into the Caliphate 's borderlands the previous year .

Unable to break Bodily_harm through the besieging army , Boiditzes , the commander of the breached section privately attempted to negotiate Communication with the Caliph without notifying his superiors .

The Battle Hostile_encounter of Tawahin ( , `` Battle Hostile_encounter of the Mills '' ) was fought Hostile_encounter in 885 between the forces of the Abbasid Caliphate under Abu ' l-Abbas ibn al-Muwaffaq ( the future Caliph al-Mu'tadid ) and the autonomous Tulunid ruler of Egypt and Syria , Khumarawayh .

By 642 AD , under Caliph Umar , Arab Muslim forces had laid Placing control Control of Mesopotamia ( 638 ) , Syria ( 641 ) , Egypt ( 642 ) , and had invaded Attack Armenia , all previously territories split Motion between the warring Hostile_encounter Byzantine and Persian Empires , and were concluding Process_end their conquest Conquering of the Persian Empire with their defeat Conquering of the Persian army at the Battle Hostile_encounter of Nahāvand .

In 644 at Madinah , Caliph Umar ( Omar ) was succeeded Change_of_leadership by Uthman ibn Affan ( Othman ) , during whose twelve-year rule Armenia , Cyprus , and all of Iran , would be added Cause_to_be_included to the growing Expansion Islamic empire ; Afghanistan and North Africa would receive Receiving major invasions Attack ; and Muslim sea raids Attack would range Cause_to_be_included from Rhodes to the southern coasts of the Iberian Peninsula .

Ultimately , abandoned GiveUp by many of their `` mawali '' auxiliaries , the Caliph 's forces were overwhelmed Destroying and defeated Conquering .