The Caliph (Arabic: خليفة; /khalīfah/ Turkish: Halife ) is the head of state in a Caliphate, and the title for the leader of the Islamic Ummah, an Islamic community ruled by the Shari'ah. It is a transcribed version of the Arabic word About this sound خليفة Khalīfah (help·info) which means "successor" or "representative". The early leaders of the Muslim nation following Muhammad's (570–632) death were called "Khalifat Rasul Allah", the political successors to the messenger of God (referring to Muhammad). Some academics prefer to transliterate the term as Khalīfah.
Caliphs were often also referred to as Amīr al-Mu'minīn (أمير المؤمنين) "Commander of the Faithful", Imam al-Ummah, Imam al-Mu'minīn (إمام المؤمنين), or more colloquially, leader of the Muslims. After the first four caliphs (Abu Bakr, Umar ibn al-Khattab, Uthman ibn Affan, and Ali ibn Abi Talib), the title was claimed by the Umayyads, the Abbasids, the Fatimids, and the Ottomans, and at times, by competing dynasties in Spain, Northern Africa, and Egypt. Most historical Muslim governors were called sultans or emirs, and gave allegiance to a caliph, but this caliph at times had very little real authority. The title has been defunct since the Republic of Turkey abolished the Ottoman Caliphate in 1924, although some individuals and groups have called for its restoration. (Hussein bin Ali, Sharif of Mecca and King of Hejaz, claimed the title briefly in 1924, and the Imams of Yemen had been using the title for centuries and continued to use the title until 1962.)
Famous and Notable Caliphs
* Abu Bakr: First rightly guided caliph. Subdued rebel tribes in the Ridda Wars.
* Umar ibn al-Khattab: Second rightly guided caliph. During his reign, the Islamic empire expanded to include Egypt, Jerusalem, and Persia.
* Uthman ibn Affan: Third rightly guided caliph. The Qur'an was compiled under his direction. Killed by rebels.
* Ali ibn Abu Talib: Fourth and last rightly guided caliph, and considered the first imam by Shi'a Muslims. His reign was fraught with internal
* Muawiya I: First caliph of the Umayyad Dynasty. Muawiya instituted dynastic rule by appointing his son Yazid as his successor, a trend that
continue through subsequent caliphates.
* Abd al-Malik ibn Marwan - Fifth caliph of Ummayad Dynasty, translated important records into Arabic, established an Islamic currency system,
led additional wars against the Byzantines and ordere construction of the Dome of the Rock.
* Umar ibn Abd al-Aziz: Umayyad caliph considered by some (mainly Sunnis) to be a fifth rightly guided caliph.
* Harun al-Rashid: Abbasid caliph during whose reign Baghdad became the world's preeminent center of trade, learning, and culture. Harun is
the subject of many stories in the famous work 1001 Arabian Nights.
* Selim I the Brave: First Caliph of the Ottoman Empire with the conquest of Egypt and the Holy Cities. Defeated the powerful Shia Safavid Empire.
* Suleiman the Magnificent: Early Ottoman Sultan during whose reign the Ottoman Empire reached its zenith.
* Abdul Mejid II: Last Caliph of the Ottoman Dynasty, the 101st Caliph in line from Caliph Abu Bakr. On August 23, 1944, Abdul Mejid II died at
his house in the Boulevard Suchet, Paris XVIe, France. He was buried at Medina, Saudi Arabia.