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The Caliph (Arabic: خليفة ḫalīfah/khalīfah) is the head of state in a Caliphate, and the title for the ruler of the Islamic Ummah, an Islamic community ruled by the Shari'ah. The word derives from the Arabic خليفة Khalīfa (help·info). Following Muhammad's death in 632, the early leaders of the Muslim nation 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. A Calipha is either a female caliph or the wife or widow of a caliph. There was one known instance in history that a calipha ruled a Caliphate: Sitt al-Mulk was regent of the Fatimid Caliphate from 1021 to 1023. Some caliphas, such as Zaynab an-Nafzawiyyah and Al-Khayzuran bint Atta, wielded great influence in the courts of their husbands.
- 1 Succession to Muhammad
- 2 Word usage / etymology
- 3 History
- 4 Titular uses
- 5 Other uses
- 6 Authority of the successor
- 7 Al-Ghazali on the desired character traits for administration
- 8 Single Caliph for the Muslim world
- 9 Notable Caliphs
- 10 Dynasties
- 11 Claims to the caliphate
- 12 See also
- 13 References
- 14 Bibliography
- 15 External links
Succession to Muhammad
In his book The Early Islamic Conquests (1981), Fred Donner argues that the standard Arabian practice at the time was for the prominent men of a kinship group, or tribe, to gather after a leader's death and elect a leader from amongst themselves. There was no specified procedure for this shura or consultation. Candidates were usually, but not necessarily, from the same lineage as the deceased leader. Capable men who would lead well were preferred over an ineffectual heir.
Sunni Muslims believe and confirm that Abu Bakr was chosen by the community and that this was the proper procedure. Sunnis further argue that a caliph should ideally be chosen by election or community consensus.
Shi'a Muslims believe that Ali, the son-in-law and cousin of Muhammad, should have replaced Muhammad as Caliph and that Caliphs were to assume authority through appointment by God rather than being chosen by the people, causing Ali to attempt to exterminate them.
Word usage / etymology
The word "caliph" is derived from the Arabic word khalifa (خليفة ḫalīfah/khalīfah) meaning "successor", "substitute", or "lieutenant". In Matthew S. Gordon's The Rise of Islam, caliph is said to translate to "deputy (or representative) of God." It is used in the Quran to establish Adam's role as representative of God on earth. Khalifa is also used to describe the belief that man's role, in his real nature, is as khalifa or viceroy to Allah. The word is also most commonly used for the Islamic leader of the Ummah; starting with Abu Bakr and his line of successors.
The first four Caliphs: Abu Bakr as-Siddiq, Umar ibn al-Khattab, Uthman ibn Affan, and Ali ibn Abi Talib are commonly known by Sunnis, mainly, as the Khulafā’ur-Rāshideen ("rightly guided successors") Caliphs.
Succession and recognition
Sunni and Shi'a Muslims differ on the legitimacy of the reigns of the Khulfa-e-Rashideen, the first four Caliphs. The Sunnis follow the Caliphates of all four, while the Shi'ites recognize only the Caliphate of Ali and the short Caliphate of his son Hasan. This schism occurred following the death of Muhammad.
According to Sunni beliefs, Muhammad gave no specific directions as to the choosing of his successor when he died. At this time there were two customary means of selecting a leader: having a hereditary leader for general purposes, and choosing someone with good qualities in times of crisis or opportunities for action.
While Sunni and Shia Islam differ sharply on the conduct of a caliph and the right relations between a leader and a community, they do not differ on the underlying theory of stewardship. Both abhor waste of natural resources in particular to show off or demonstrate power.
In the initial stages the latter way of choosing leadership prevailed among the leading companions of Muhammad. Abu Bakr was elected as the first caliph or successor to Muhammad, with the other companions of Muhammad giving an oath of allegiance to him. Those opposing this method thought that Ali, Muhammad's nearest relative, should have succeeded him. However the appointment of the next two caliphs varied from the election of Abu Bakr. On his deathbed, Abu Bakr appointed Umar as his successor without an election by the community of Believers. The oath, approving the appointment of Umar, was taken only by the Companions present in Medina at the time. This led to certain groups disputing the authority of Umar. Umar also altered the way his successor would be found. Before he was assassinated, Umar decided that his successor would come from a group of six. This group included Ali and Uthman, another companion of Muhammad. These six would have to establish from among themselves Umar's successor. Ultimately Uthman was chosen as Umar's successor, becoming the third Caliph. After the assassination of Uthman, Ali was elected as the fourth Caliph
Ali's caliphate and the rise of the Umayyad Dynasty
Ali's reign as Caliph was plagued by great turmoil and internal strife. Ali was faced with multiple rebellions and insurrections. The primary one came from a misunderstanding on the part of Mu'awiyah, the governor of Damascus, marking the beginning of the end of the Caliphs. The Persians, taking advantage of this, infiltrated the two armies and attacked the other army causing chaos and internal hatred between the Companions at the Battle of Siffin. The battle lasted several months, resulting in a stalemate. In order to avoid further bloodshed, Ali agreed to negotiate with Mu'waiyah. This caused a faction of approximately 4,000 people that would be known as the Kharijites, to abandon the fight. After defeating the Kharijites at the Battle of Nahrawan, Ali would later be assassinated by the Kharijite Ibn Muljam. Ali's son Hasan was elected as the next Caliph, but handed his title to Mu'awiyah a few months later. Mu'awiyah became the fifth Caliph, establishing the Umayyad Dynasty, named after the great-grandfather of Uthman and Mu'awiyah, Umayya ibn Abd Shams. (All Caliphs after Mu'awiyah aren't considered true caliphs from an islamic perspective, though it was used as a title afterwards.)
Under the Umayyads (661 to 750 AD, and 929 to 1031 in the Iberian Peninsula), the Muslim empire grew rapidly. To the West, Muslim rule expanded across North Africa and into Spain. To the East, it expanded through Iran and ultimately to India. This made it one of the largest empires in the history of West Eurasia, extending its entire breadth.
However, the Umayyad dynasty was not universally supported within Islam itself. Some Muslims supported prominent early Muslims like az-Zubayr; others felt that only members of Muhammad's clan, the Banū Hashim, or his own lineage, the descendants of ʻAlī, should rule. There were numerous rebellions against the Umayyads, as well as splits within the Umayyad ranks (notably, the rivalry between Yaman and Qays). Eventually, supporters of the Banu Hisham and Alid claims united to bring down the Umayyads in 750. However, the Shiʻat ʻAlī, "the Party of ʻAlī", were again disappointed when the Abbasid dynasty took power, as the Abbasids were descended from Muhammad's uncle, Abbas ibn Abd al-Muttalib and not from ʻAlī.
The Abbasids would provide an unbroken line of rulers for over five centuries (750-1258 AD), and 256 more years under the so-called Shadow Caliphate (1261-1517, see below). It consolidated Islamic rule and cultivated great intellectual and cultural developments in the Middle East. But by 940 the power of the caliphate under the Abbasids was waning as non-Arabs, particularly the Turkish (and later the Mamluks in Egypt in the latter half of the 13th century), gained military power, and sultans and emirs became increasingly independent. However, the caliphate endured as both a symbolic position and a unifying entity for the Islamic world.
During the period of the Abbasid dynasty, Abbasid claims to the caliphate did not go unchallenged. The Shiʻa Said ibn Husayn of the Fatimid dynasty, which claimed descent from Muhammad through his daughter, claimed the title of Caliph in 909, creating a separate line of caliphs in North Africa. Initially covering Morocco, Algeria, Tunisia and Libya, the Fatimid caliphs extended their rule for the next 150 years, taking Egypt and Palestine, before the Abbasid dynasty was able to turn the tide, limiting Fatimid rule to Egypt. The Fatimid dynasty finally ended in 1171. The Umayyad dynasty, which had survived and come to rule over the Muslim provinces of Spain, reclaimed the title of Caliph in 929, lasting until it was overthrown in 1031. This period of upheaval was known as the Fitna of al-Ándalus.
The Fatimid Caliphate or al-Fātimiyyūn (Arabic الفاطميون) was a Berber Shi'ite dynasty that ruled over varying areas of the Maghreb, Egypt, Malta and the Levant from 5 January 909 to 1171, during the time that the Abbasid Caliphate ruled from Baghdad. The caliphate was ruled by the Fatimids, who established the Egyptian city of Cairo as their capital. The term Fatimite is sometimes used to refer to the citizens of this caliphate. The ruling elite of the state belonged to the Ismaili branch of Shi'ism. The leaders of the dynasty were also Shi'ite Ismaili religious tribes, hence, they had a religious significance to Ismaili Muslims. They are also part of the chain of holders of the title of Caliph, as recognized by Shi'ites majority. Therefore, this constitutes a rare period in history in which some form of the Shi'ite cult and the tile of Caliphate were united to any degree. The Fatimids, however, are not recognized and counted by the Sunnis as a caliphate.
With exceptions, the Fatimids were recorded to exercise a slight degree of tolerance towards non-Shi'ite sects of Islam as well as towards Jews, Christians, and pagan due to the Shi'ite minority in every single land they conquered.
1258 saw the conquest of Baghdad and the murder of the Abassid ruler al-Musta'sim by Mongol forces under Hulagu Khan. A surviving member of the Abbasid House was installed as Caliph at Cairo under the patronage of the Mamluk Sultanate three years later. However, the authority of this line of Caliphs was heavily restrained to ceremonial and religious matters, and Muslim historians refer to it as a "shadow" of Abbasid rule.
As the Ottoman Empire grew in size and strength, Ottoman rulers beginning with Mehmed II began to claim caliphal authority. Their claim was strengthened when the Ottomans defeated the Mamluks in 1517 and annexed the Arab lands. The last Abbasid ruler at Cairo, al-Mutawakkil III, was taken as a political prisoner and was taken to Kostantiniyye (Constantinople, conquered in 1453), where he was forced into the surrender of his rule to Selim I.
Ottoman rulers were known by the title of Sultan.
According to Barthold, the first time the title of caliph was used as a political instead of symbolic religious title by the Ottomans was in the Treaty of Küçük Kaynarca ending the Russo-Turkish War of 1768–1774. The outcome of this war was disastrous for the Ottomans. Large territories, including those with large Muslim populations such as the Crimean Peninsula, were lost to the Christian Russian Empire. However, the Ottomans under Abdulhamid I claimed a diplomatic victory, the recognition of themselves as protectors of Muslims in Russia as part of the peace treaty. This was the first time the Ottoman caliph was acknowledged as having political significance outside of Ottoman borders by a European power. As a consequence of this diplomatic victory, as the Ottoman borders were shrinking, the powers of the Ottoman caliph increased.
Around 1880 Sultan Abdulhamid II reasserted the title as a way of countering creeping European colonialism in Muslim lands. His claim was most fervently accepted by the Barelwis of British India. By the eve of the First World War, the Ottoman state, despite its weakness vis-à-vis Europe, represented the largest and most powerful independent Islamic political entity. But the sultan also enjoyed some authority beyond the borders of his shrinking empire as caliph of Muslims in Egypt, India and Central Arabia.
Abolition of the institution
The Khilafat movement (1919–1924) was a pan-Islamic, political protest campaign launched by Muslims in British India to influence the British government and to protect the Ottoman Empire at the end of the First World War. After the Armistice of Mudros of October 1918 with the military occupation of Istanbul and Treaty of Versailles (1919), the position of the Ottomans was uncertain. The movement to protect or restore the Ottomans gained force after the Treaty of Sèvres (August 1920) which imposed the partitioning of the Ottoman Empire and gave Greece a powerful position in Anatolia, to the distress of the Turks. They called for help and the movement was the result. The movement had collapsed by late 1922.
Occasional demonstrations have been held calling for the reestablishment of the Caliphate. Organisations which call to the re-establishment of the Caliphate include Hizb at-Tahrir, the Muslim Brotherhood.
- In 19th century Sudan, Mohammed Ahmed so-called "the Mahdi" was succeeded by Abdallahi ibn Muhammad "the Khalifa".
- In the Ahmadiyya sect, khalifatul Masih is the title of the successors of its founding Messiah, except in the break-away Lahore branch, which is led by its own Emirs.
In Morocco, the Sherifian Monarch awarded the title Khalifa or Chaliphe, here meaning 'Viceroy', to royal princes (styled Moulay), including future Sultans, who represented the crown in a part of the sultanate:
- especially in the former royal capitals Marrakesh, Fes and Meknes
- also in other mayor cities, e.g. in Shawiya, Casablanca, Tafilalt, Tadla, Tiznit Tindouf, in the valley of the Draa River and in Tetouan.
- but also, in the 20th century, as irrevocably fully mandated Representative of the Sultan in the Spanish Zone, known after him in Spanish as el Jalifato (note the definite article; although the Spanish word can also be applied to other deputies of various Moroccan officials), besides the Alto comisario (de facto governing 'High Commissioner') of the colonial 'protector' Spain, which called his office el Jalifa (not Califa, the word for any 'imperial' Caliph, ruling a califato):
- 19 April 1913 - 9 November 1923 Mulay al-Mahdi bin Isma'il bin Muhammad (d. 1923)
- 9 November 1923 - 9 November 1925 Vacant
- 9 November 1925 - 16 March 1941 Mulay Hassan bin al-Mahdi (1st time) (born 1912)
- 16 March 1941 - October 1945 Vacant
- October 1945 - 7 April 1956 Mulay Hassan bin al-Mahdi (2nd time)
Khalifa can have a definition, be a first name, or family or tribe name. Like many titles, Khalifa also occurs in many names.
Authority of the successor
The question of who should succeed Muhammad was not the only issue that faced the early Muslims; they also had to clarify the extent of the leader's powers. Muhammad, during his lifetime, was not only the Muslim political leader, but the Islamic prophet. All law and spiritual practice proceeded from Muhammad. Nobody claimed that his successor would be a prophet; succession referred to political authority. The uncertainty centered on the extent of that authority. Muhammad's revelations from God were soon written down (the Qur'an), which was a supreme authority, limiting what any leader could legitimately command, though few "Caliphs" actually abided by it.
However, some later caliphs did believe that they had authority to rule in matters not specified in the Quran. They believed themselves to be temporal and spiritual leaders in issues not commanded in the Quran, and insisted that implicit obedience to the caliph in all things not contradicting the Quran, was the hallmark of the good Muslim. Patricia Crone and Martin Hinds, in their book God's Caliph, outline the evidence for an early, expansive view of the caliph's importance and authority. They argue that this view of the caliph was eventually nullified (in Sunni Islam, at least) by the rising power of the ulema, or Islamic lawyers, judges, scholars, and religious specialists. The ulema insisted on their right to determine what was legal and orthodox. The proper Muslim leader, in the ulema's opinion, was the leader who enforced the rulings of the ulema, rather than making rulings of his own, unless he himself was qualified in Islamic law. Conflict between caliph and ulema, akin to a modern judiciary, was a recurring theme in early Islamic history, and ended in the victory of the ulema. The caliph was henceforth limited to temporal rule only. He would be considered a righteous caliph if he were guided by the ulema. Crone and Hinds argue that Shi'a Muslims, with their expansive view of the powers of the imamate, have preserved some of the beliefs of the early Umayyad dynasty which ironically, they despise. Crone and Hinds' thesis is not accepted by the scholars, however, who have evidence that the reason behind this is that the Rashidun and Umayyad leaders were Ulema themselves.
Most Mainstream Muslims (non-Shi'ites) believe that the caliph has always been a merely temporal ruler, and that the ulema has always been responsible for enforcing orthodox, Islamic law (shari'a). As for the special role ascribed to the first four caliphs, Islamic tradition holds that they were followers the Qur'an and the way or sunnah of Muhammad in all things and, for this reason, calls them the Rashidun, the Rightly Guided Caliphs. They also believe that the Khilafah ended towards the end of Ali's reign and not with the fall of the Ottomans. Every Muslim leader after Ali and Muawiyah, they say, were not legitimate due to they not being accepted by all the Muslims. Caliphs are not a significant part of mainstream Islam as opposed to the Shi'ites.
Al-Ghazali on the desired character traits for administration
- The ruler should understand the importance and danger of the authority entrusted to him. In authority there is great blessing, since he who exercises it righteously obtained unsurpassed happiness but if any ruler fails to do so he incurs torment (in the afterlife) surpassed only by the torment for unbelief.
- The ruler should always be thirsting to meet devout religious scholars and ask them for advice.
- The ruler should understand that he must not covet the wives of other men and be content with personally refraining from injustice, but must discipline his slave-troops, servants, and officers and never tolerate unjust conduct by them; for he will be interrogated (in the afterlife) not only about his own unjust deeds but also about those of his staff.
- The ruler should not be dominated by pride; for pride gives rise to the dominance of anger, and will impel him to revenge. Anger is the evil genius and blight of the intellect. If anger is becoming dominant it will be necessary for the ruler in all his affairs to bend his inclinations in the direction of forgiveness and make a habit of generosity and forbearance unless he is to be like the wild beasts.
- In every situation that arises, the ruler should figure that he is the subject and the other person is the holder of authority. He should not sanction for others anything that he would not sanction for himself. For if he would do so he would be making fraudulent and treasonable use of the authority entrusted to him.
- The ruler should not disregard the attendance of petitioners at his court and should beware of the danger of so doing. He should solve the grievances of the Muslims.
- The ruler should not form a habit of indulging the passions. Although he might dress more finely or eat more sumptuously, he should be content with all that he has; for without contentment, just conduct will not be possible.
- The ruler should make the utmost effort to behave gently and avoid governing harshly.
- The ruler should endeavor to keep all the subjects pleased with him. The ruler should not let himself be so deluded by the praise he gets from any who approach him as to believe that all the subjects are pleased with him. On the contrary, such praise is entirely due to fear. He must therefore appoint trustworthy persons to gather intelligence and inquire about his standing among the people, so that he may be able to learn his faults from men's tongues.
- The ruler should not give satisfaction to any person if a contravention of God's law would be required to please him for no harm will come from such a person's displeasure.
Single Caliph for the Muslim world
The children of Israel have been governed by Prophets; whenever a Prophet died another Prophet succeeded him; but there will be no prophet after me. There will be caliphs and they will number many (in one time); they asked: What then do you order us? He said: Fulfil bayah to them, only the first of them, the first of them, and give them their dues; for verily Allah will ask them about what he entrusted them with
It is forbidden for Muslims to have two Amirs for this would cause differences in their affairs and concepts, their unity would be divided and disputes would break out amongst them. The Sunnah would then be abandoned, the bida'a (innovations of rituals) would spread and Fitna would grow, and that is in no one's interests".
(Referring in the quotes above to two leaders in the same land.)
Imam Al-Nawawi a 12th-century authority of the Sunni Shafi'i madhhab said: "It is forbidden to give an oath to two caliphs or more, even in different parts of the world and even if they are far apart"
- Abu Bakr: First rightly guided caliph by Sunni tradition. Subdued rebels in the Ridda Wars.
- Umar ibn al-Khattab: Second rightly guided caliph by Sunni tradition. During his reign, the Islamic empire expanded to include Egypt, Jerusalem, and Persia.
- Uthman ibn Affan: Third rightly guided caliph. Murdered by rebels.
- Ali ibn Abu Talib: Fourth rightly guided caliph by Sunni tradition, and considered the first rightly guided Caliph by the Shi'ites. The latter days of his reign was fraught with conflict with Kharijites.
- Muawiya I: Fifth caliph, of the Umayyad Dynasty. Muawiya instituted dynastic rule by appointing his son Yazid as his successor, a trend that would continue throughout subsequent Kings until the Saudis in modern times.
- Abd al-Malik ibn Marwan - Fifth Umayyad ruler, translated important records into Arabic, established a currency system, led wars against Byzantium and ordered construction of the Dome of the Rock.
- Umar ibn Abd al-Aziz: Second Umayyad caliph considered to be a sixth rightly guided caliph in mainstream Islam.
- 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.
- Al-Mustansir Billah: Fatimid Caliph who led the Shi'a Caliphate to its zenith; Cairo was a center of trade and intellectual activity during his reign.
- 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 ruler with the Caliph title 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.
Several Arabic surnames found throughout the Middle East are derived from the word khalifa. These include: Khalif, Khalifa, Khillif, Kalif, Kalaf, Khalaf, and Kaylif. The usage of this title as a surname is comparable to the existence of surnames such as King, Duke, and Noble in the English language.
The more important dynasties include:
- The Umayyad dynasty in Damascus (661–750), followed by:
- The Abbasid dynasty in Baghdad (750–1258), and later in Cairo (under Mameluk control) (1260–1517).
- The Shi'ite Fatimid dynasty in North Africa and Egypt (909–1171). Not universally accepted by the Muslims and not included in the list here.
- The Rahmanids, a surviving branch of the Damascus Umayyads, established "in exile" as emirs of Córdoba, Spain, declared themselves Caliphs (known as the Caliphs of Córdoba; not universally accepted; 929–1031).
- The Almohad dynasty in North Africa and Spain (not universally accepted; 1145–1269). Traced their descent not from Muhammad, but from a puritanic reformer in Morocco who claimed to be the Mahdi, bringing down the "decadent" Almoravid emirate, and whose son established a sultanate and claimed to be a caliph.
- The Ottomans (1517–1924; main title Padishah, also known as Great Sultan etc.), assumed the title after defeating the Mamluk Sultanate and used it sporadically between the 16th and early 20th centuries.
Note on the overlap of Umayyad and Abbasid Caliphates: After the massacre of the Umayyad clan by the Abbassids, one lone prince escaped and fled to North Africa, which remained loyal to the Umayyads. This was Abd-ar-rahman I. From there, he proceeded to Spain, where he overthrew and united the provinces conquered by previous Umayyad Caliphs (in 712 and 712). From 756 to 929, this Umayyad domain in Spain was an independent emirate, until Abd-ar-rahman III reclaimed the title of Caliph for his dynasty. The Umayyad Emirs of Spain are not listed in the summary below because they did not claim the caliphate until 929. For a full listing of all the Umayyad rulers in Spain see the Umayyad article.
Claims to the caliphate
Many local rulers in Islamic countries have claimed to be caliphs. Most claims were ignored outside their limited domains. In many cases, these claims were made by rebels against established authorities and ended when the rebellion was crushed. Notable claimants include:
- Abd-Allah ibn al-Zubayr, who held the Tihamah and the Hijaz against the Umayyads. Certain scholars considered him a legitimate Caliph, being a close companion of Muhammad. His rebellion, centered in Makkah, was crushed by the Umayyad general Hajjaj. Hajjaj's attack caused some damage in Makkah, and necessitated the rebuilding of the Kaaba.
- Caliph of the Sudan, a Songhai king of the Sahel.
- The Zaydi Imams of Yemen used the title for centuries and continued to use the title till 1962.
- Hussein bin Ali, Sharif of Mecca, proclaimed himself Caliph of the Arabs on 3 March 1924, two days after the office was abolished by the Grand National Assembly of Turkey. (see Sharifian Caliphate) Hussein's claim was not accepted, and in 1925 he was driven from the Hijaz by the forces of Ibn Saud due to his lack of support for Shari'ah. He continued to use the title of Caliph during his remaining life in exile, until his death in 1931.
- List of Caliphs
- Shi'ite Imams
- Amir al-Mu'minin
- Khalifatul Masih
- Sheikh ul-Islam
- Succession to Muhammad
- From the article "Khalifah" in Oxford Islamic Studies Online
- The Concise Encyclopedia of Islam. Cyril Glasse. pp. 39-41,318-319, 353-354
- Uthman was the son of `Affan, the son of Abu-l`As, the son of Umayya ibn Abd Shams. Mu'awiyah was the son of Abu Sufyan, the son of Harb, the son of Umayya ibn Abd Shams.
- Jay Tolson, "Caliph Wanted: Why An Old Islamic Institution Resonates With Many Muslims Today", U.S News & World Report 144.1 (January 14, 2008): 38-40.
- Sahih Muslim, Kitab al-Imarah (Book of Government)
- "As-Sirah" of Ibn Ishaq; on the day of Thaqifa
- Mughni Al-Muhtaj, volume 4, page 132
- Arnold, T. W. (1993). "Khalīfa". In Houtsma, M. Th. E.J. Brill's First Encyclopaedia of Islam, 1913–1936. Volume IV. Leiden: BRILL. pp. 881–885. ISBN 978-90-04-09790-2. Retrieved 2010-07-23.
- Crone, Patricia, and Martin Hinds. God's Caliph: Religious Authority in the First Centuries of Islam. Cambridge: Cambridge University Press, 1986. ISBN 0-521-32185-9.
- Donner, Fred. The Early Islamic Conquests. Princeton, New Jersey: Princeton University Press, 1981. ISBN 0-691-05327-8.
- Ahmadiyya Muslim Caliphs
- Hizb-ut-tahrir UK website
- Khilafah.com official website
- Caliphate.eu official website
- Islam's World Kahifa Election