Deen

How Sunni and Shia Came to Be

The succession question, the scriptural evidence on both sides in their own terms, and the timeline of a divergence that took three centuries to finish.

Mohammad Siddiqui

— 98 min read
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How Sunni and Shia Came to Be, part one of three
Part one of three

The succession question, the scriptural evidence on both sides in their own terms, and the timeline of a divergence that took three centuries to finish.

Mohammad Siddiqui, min readSeven sections · 21 verses and reportsSources throughout

New to the Qur'an, or to this series? Start with The Qur'an: What It Is, How It Came Down, and How It Was Kept, then read Muhammad ﷺ: A Life. All articles: Deen: Start Here.

I

What the argument is actually about

It is tempting to say the split is about who should have led after the Prophet ﷺ. That is the presenting symptom. Three distinct questions are tangled together, and the traditions differ on all three, the second one most consequentially.

Question one

Who was to succeed him?

SunniHe appointed no one in binding terms, leaving the community to choose. Abū Bakr, ʿUmar, ʿUthmān and ʿAlī, the Rāshidūn, held the office legitimately, in that order.1718
Twelver & IsmailiHe designated ʿAlī explicitly, by naṣṣ, clear textual designation, at Ghadīr Khumm and elsewhere. The community failed to honour it.2921
ZaydiʿAlī was the most worthy, but the first caliphs are not condemned as usurpers. Any qualified descendant who rises in arms is Imam.36
Question two, the deep one

What kind of office is it?

KhilāfaExecutive and political leadership. The caliph enforces the law; he does not author or receive it. He can err, and is not a source of religious knowledge, that sits with the scholars and the transmitted texts.
ImāmaA divinely appointed office. The Imam is maʿṣūm, protected from sin and error, the authoritative interpreter of revelation, holding inherited knowledge, the necessary link between God and creation in every age.

Losing the argument about who would matter far less if both sides agreed the office was purely executive. They do not, and Sunni theory does not hold it merely administrative either: al-Māwardī defines the caliphate as a religious obligation of the community.17

Question three

Whose transmission is reliable?

Sunni methodAuthenticate by the chain (isnād) back to the Prophet through the Companions, whose collective probity is a working presumption of the system.
Shia methodAdmit reports from the Prophet and the Imams;10 rijāl grades transmitters partly by doctrinal affiliation, so Companions who opposed ʿAlī are not neutral conduits. Not purely confessional, though: the category muwaththaq accepts a reliable but non-Imāmī transmitter, and thousands of such reports are relied on.

The two traditions do not merely disagree about conclusions. They disagree about what counts as evidence, which is why sincere, rigorous scholars reach incompatible results.

Not in dispute: the text of the Qur'an. Both traditions use the identical muṣḥaf. The accusation that Shia hold it corrupted (taḥrīf) is rejected by mainstream Twelver scholarship, explicitly by al-Ṣadūq (d. 991), al-Ṭūsī (d. 1067), and at length by al-Khū'ī in al-Bayān.1121
II

The evidence, and both readings of it

The Qur'an nowhere names a successor; both traditions accept this at the literal level.1 Every verse below needs an external narration to fix its referent, which is why the argument moves immediately to hadith, and why the hadith canon question is the real fault line.

The same word, two different roads. An isnād is a chain of named people. The Sunni chain runs through the Companions; the Shia chain runs through the Imams. Both authenticate by continuity and transmitter reliability, but a Companion who opposed ʿAlī is not a neutral conduit on one side, and the presumption of collective Companion probity is load-bearing on the other. This is why the two systems cannot validate each other: they disagree at the intake stage about who counts.

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III

The timeline, in five phases

The split is a process, not an event. Dots on the rail mark the turning points; gold marks the moments after which the picture cannot be put back.

The gap is the finding. The political rupture and the doctrinal rupture are not the same event and are not close together. A century separates the end of the first civil wars from the beginning of the doctrinal formation, and the Sunni hadith canon, the creed schools and the name itself all fall in the third band, two hundred years downstream of Karbala.

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IV

The branch tree

One framing error to clear first. Popular diagrams draw Islam as a tree with mutually exclusive branches. For Sunnism this is simply wrong: law (madhhab), creed (ʿaqīda) and Sufi order (ṭarīqa) are three independent axes, not alternatives. A Turkish Muslim is typically Ḥanafī in law and Māturīdī in creed and possibly Naqshbandī in ṭarīqa, simultaneously and without contradiction.

Default pairings worth knowing: Ḥanafī ↔ Māturīdī · Shāfiʿī and Mālikī ↔ Ashʿarī · Ḥanbalī ↔ Atharī. Tendencies, not rules. Tap any branch to open it.

V

What is actually shared

After all the disputes, the proportion is easy to lose. A Sunni and a Shia pray toward the same point, in the same language, at the same times, with, allowing for the hands and the combining, nearly the same actions.

Held in common

  • The shahāda
  • The same Qur'an, word for word
  • The five daily prayers
  • The fast of Ramadan
  • Zakat
  • The hajj, same Kaʿba, same month
  • The finality of Muhammad's ﷺ prophethood
  • The same angels, prophets, scriptures, resurrection and judgement
  • The same moral law in the overwhelming majority of its content
  • The same core of fiqh in worship, transactions and family law
PracticeSunniShia (Twelver)
Prayer timesFive distinctCommonly combined into three sittings
Hands in prayerFolded, or at the sides in MālikīAt the sides (sadl)
AdhanStandardAdds ḥayya ʿalā khayr al-ʿamal; commonly a testimony to ʿAlī's wilāya, held recommended rather than part of the adhan
ProstrationAny pure surfaceCommonly a turba, a tablet of earth, often from Karbala
WuḍūʾWashing the feetWiping the feet
MutʿaProhibited, held abrogatedPermitted
TaxationZakatZakat and khums, a fifth, half to the sayyids, half to the marjaʿ
InheritanceA daughter takes her Qur'anic half; the residue passes to the male agnates (ʿaṣaba)The residue returns to the daughter by radd; collaterals are excluded while a direct descendant survives
Legal authorityThe four madhāhib; no living authority bindingBinding taqlīd of a living marjaʿ al-taqlīd
CalendarShared, plus regional practiceShared, plus Āshūrāʾ mourning, Arbaʿīn, ʿĪd al-Ghadīr

None of these is trivial to the people practising them. None of them is the reason the traditions exist separately. The reason is question two: what kind of office succeeded the Prophet, and therefore who has the authority to settle a table like this one.

VI

Three things worth carrying away

Political before theological

On the reading of modern historical scholarship, the theology was built afterwards, on both sides, to explain positions taken for reasons of politics, tribe and grief. This is not cynical and it does not delegitimise either tradition, theology developed in response to crisis is still theology. But the order matters. Nobody in 632 was arguing about the ontology of the Imamate.2523

The evidence is not hidden

Ghadīr Khumm is in Tirmidhī.2 Thaqalayn is in Muslim.3 Manzila is in Bukhārī.4 The Twelve is in both Ṣaḥīḥs.5 The Qirṭās incident is in Bukhārī several times over.6 Fāṭima's displeasure with Abū Bakr is in Bukhārī.7 None of these needs taking on trust: each is in a Sunni collection, with a number anyone can look up.9

The sects are younger than the arguments

By a lot. Take the century between the political rupture and the doctrinal one, and the further gap before either tradition had a fixed canon, a settled law and a name for itself. The claim to be the original from which the other departed is a claim about the seventh century sustainable only with ninth-century evidence.1920

VII

Glossary

#

Every technical term used on this page, in one place. The first appearance of each in the text above carries its definition on hover or focus.

VIII

Sources

Scriptural

  1. The Qur'an, cited by sūra:āya; English quotations in the evidence cards from Mustafa Khattab, The Clear Quran; every verse checkable at quran.com
  2. Jāmiʿ al-Tirmidhī 3713, “For whomever I am his Mawlā, then ʿAlī is his Mawlā”; graded ṣaḥīḥ (Darussalam)
  3. Ṣaḥīḥ Muslim 2408a, the address at the pool of Khumm: “two weighty things”, the Book of God and the people of the Prophet's house
  4. Ṣaḥīḥ al-Bukhārī 4416, “like Aaron to Moses, but there will be no prophet after me”, at Tabūk
  5. Ṣaḥīḥ al-Bukhārī 7222, twelve rulers, “all of them from Quraysh”, from Jābir b. Samura
  6. Ṣaḥīḥ al-Bukhārī 114, the request for writing material in the final illness (the Qirṭās incident)
  7. Ṣaḥīḥ al-Bukhārī 4240–4241, Fāṭima's claim to the inheritance, her anger with Abū Bakr, her death six months after the Prophet, and ʿAlī's pledge after it
  8. Ṣaḥīḥ al-Bukhārī 6830, ʿUmar's own account of the Saqīfa: the pledge to Abū Bakr as a falta, and the warning against pledging without consulting the Muslims
  9. Ṣaḥīḥ al-Bukhārī · Ṣaḥīḥ Muslim · Sunan Abī Dāwūd · Jāmiʿ al-Tirmidhī · Sunan al-Nasāʾī · Sunan Ibn Mājah · Musnad Aḥmad, every number here is checkable at sunnah.com
  10. al-Kulaynī, al-Kāfī · Ibn Bābawayh al-Ṣadūq, Man lā yaḥḍuruhu al-faqīh · al-Ṭūsī, Tahdhīb al-aḥkām and al-Istibṣār · Nahj al-Balāgha, texts at al-islam.org
  11. Abū al-Qāsim al-Khūʾī, al-Bayān fī tafsīr al-Qurʾān, translated by Abdulaziz Sachedina as The Prolegomena to the Qur'an (Oxford University Press, 1998); the section on taḥrīf

Classical

  1. al-Ṭabarī, Taʾrīkh al-rusul wa'l-mulūk; in English, The History of al-Ṭabarī, vol. 9: The Last Years of the Prophet, trans. Ismail K. Poonawala (SUNY Press, 1990), which carries the Saqīfa narratives
  2. The History of al-Ṭabarī, vol. 19: The Caliphate of Yazīd b. Muʿāwiyah, trans. I. K. A. Howard (SUNY Press, 1991), the events of the year 61 and Karbala
  3. Ibn Saʿd, al-Ṭabaqāt al-kubrā · al-Balādhurī, Ansāb al-ashrāf · al-Yaʿqūbī, Taʾrīkh · al-Masʿūdī, Murūj al-dhahab
  4. Ibn Ḥajar al-ʿAsqalānī, Fatḥ al-Bārī · al-Nawawī, Sharḥ Ṣaḥīḥ Muslim
  5. al-Shahrastānī, al-Milal wa'l-niḥal · al-Ashʿarī, Maqālāt al-Islāmiyyīn · al-Nawbakhtī, Firaq al-Shīʿa, the heresiographies, and the primary source for most extinct groups named here
  6. al-Māwardī, al-Aḥkām al-sulṭāniyya, ch. 1 on the imamate; in English, The Ordinances of Government, trans. Wafaa H. Wahba (Garnet, 1996)

Modern academic

  1. Wilferd Madelung, The Succession to Muhammad: A Study of the Early Caliphate (Cambridge University Press, 1997)
  2. Christopher Melchert, The Formation of the Sunni Schools of Law, 9th–10th Centuries C.E. (Brill, 1997)
  3. Jonathan A. C. Brown, The Canonization of al-Bukhārī and Muslim (Brill, 2007)
  4. Moojan Momen, An Introduction to Shiʿi Islam: The History and Doctrines of Twelver Shiʿism (Yale University Press, 1985)
  5. Farhad Daftary, The Ismāʿīlīs: Their History and Doctrines (Cambridge, 2nd ed. 2007)
  6. Hossein Modarressi, Crisis and Consolidation in the Formative Period of Shiʿite Islam (Darwin Press, 1993)
  7. Haykel & Zysow, "What makes a madhhab a madhhab", Arabica
  8. Marshall G. S. Hodgson, The Venture of Islam, vol. 1: The Classical Age of Islam (University of Chicago Press, 1974)
  9. Rula Jurdi Abisaab, Converting Persia: Religion and Power in the Safavid Empire (I. B. Tauris, 2004)
  10. Rainer Brunner, Islamic Ecumenism in the 20th Century: The Azhar and Shiism between Rapprochement and Restraint (Brill, 2004), the standard study of the Azhar's dealings with Shiʿism, including Shalṭūt's fatwa

Reference works

  1. Encyclopaedia Iranica, “Ḡadīr Ḵomm” (2000): the date, 18 Ḏu'l-ḥejja 10 / 16 March 632, and the Sunni and Shiʿi readings
  2. WikiShia, “Event of Ghadir”, the Twelver account, with its listing of Sunni and Shia transmitters and of al-Amīnī's al-Ghadīr
  3. Wilferd Madelung, “Ḥosayn b. ʿAli i. Life and significance in Shiʿism”, Encyclopaedia Iranica (2004): killed 10 Moḥarram 61 / 10 October 680, with seventy or seventy-two of his party
  4. Encyclopædia Britannica, “Battle of Karbala”
  5. Saïd Amir Arjomand, “Ḡayba”, Encyclopaedia Iranica: the Kaysānī origins of the idea, the minor occultation 260–329 / 874–941, and the four deputies
  6. Heinz Halm, “ʿAskarī, Abū Moḥammad Ḥasan”, Encyclopaedia Iranica: died at Sāmarrā 8 Rabīʿ I 260 / 1 January 874 “without leaving any obvious heirs”, and the groups that formed after
  7. Encyclopædia Britannica, “Ismāʿīl I, shah of Iran”: Tabriz taken and Shiʿism proclaimed the established religion in 1501
  8. Encyclopaedia Iranica, Kaysāniya, Ghayba, Akbāriya, Shaykhism, Carmatians, Nizār, Moḥammad b. Noṣayr, Ahl-e Ḥaqq, Kolaynī
  9. Institute of Ismaili Studies, Madelung on the Zaydiyya

Living authorities

  1. Stimson Center, Middle East Program, “Navigating the Succession to Grand Ayatollah Sistani” (2026), written as he nears his 96th birthday
  2. Official website of the office of Grand Ayatollah al-Sistani, Najaf
  3. AKDN, “Prince Rahim Aga Khan V named 50th Hereditary Imam of the Shia Ismaili Muslims” (February 2025)

Demography

  1. Pew Research Center, Mapping the Global Muslim Population (7 October 2009): Sunni 87–90%, Shia 10–13%
  2. Pew, Sunni and Shia Muslims (2011)
  3. Pew Research Center, “Countries with the most Muslims and global Muslim population change, 2010–2020” (9 June 2025): 2.0 billion Muslims in 2020, with no Sunni/Shia breakdown

Pew measured the Sunni/Shia split only. There is no reliable global census of madhhab affiliation anywhere. Every percentage circulating online traces back to unsourced estimates, figures here are directional.

Ecumenical

  1. The Amman Message (9 November 2004) and its Three Points, agreed by some 200 scholars from 50 countries in July 2005 and later endorsed by more than 500: the validity of the eight recognised madhāhib, Ḥanafī, Mālikī, Shāfiʿī, Ḥanbalī, Jaʿfarī, Zaydī, Ibāḍī, Ẓāhirī, and the prohibition of takfīr between them
  2. Shaykh Maḥmūd Shalṭūt's al-Azhar fatwa (1959) recognising Jaʿfarī jurisprudence as a school Sunnis may follow; the context is in Brunner (source 27)
  3. Ṣaḥīḥ al-Bukhārī 4350, Burayda's complaint about ʿAlī from the Yemen expedition, in al-Bukhārī's Ṣaḥīḥ
  4. al-Mawsūʿa al-Ḥadīthiyya, dorar.net, search results for ʿUmar's congratulation at Ghadīr: al-Būṣīrī, Itḥāf al-khiyara 7/212; al-Albānī, Hidāyat al-ruwāh 6049; Ibn Kathīr, al-Bidāya 5/185; al-Arnaʾūṭ's notes to Musnad Aḥmad 18479–18480
  5. Muwaṭṭaʾ Mālik, Book 46, Hadith 3, “the Book of Allah and the Sunna of His Prophet”, given by Mālik without a chain
  6. Ṣaḥīḥ al-Bukhārī 3094, from Mālik b. Aws: ʿUmar asks the Companions to confirm “we are not inherited from”, in al-Bukhārī's Ṣaḥīḥ
  7. al-Mawsūʿa al-Ḥadīthiyya, dorar.net, search results for al-Shaʿbī's report of Abū Bakr visiting Fāṭima: Ibn Kathīr, al-Bidāya wa-l-nihāya 5/252, on al-Bayhaqī's chain
  8. Ṣaḥīḥ al-Bukhārī 678 (Abū Mūsā), 681 (Anas) and 683 (ʿĀʾisha), in al-Bukhārī's Ṣaḥīḥ
  9. al-Mawsūʿa al-Ḥadīthiyya, dorar.net, search results for the “ship of Noah” report: al-Haythamī, Majmaʿ al-zawāʾid 9/171; al-Sakhāwī, al-Buldāniyyāt 186; al-Ṭabarānī, al-Muʿjam al-ṣaghīr
  10. Ibn Kathīr, Tafsīr al-Qurʾān al-ʿaẓīm, on Qurʾān 5:55 (Arabic): “wa-laysa yaṣiḥḥu shayʾun minhā bi-l-kulliyya li-ḍaʿf asānīdihā wa-jahālat rijālihā”, quran.com
  11. Shāh Walī Allāh al-Dihlawī, on the charge of irjāʾ against Abū Ḥanīfa (faith and deeds), trans. Muhammadullah Khalili Qasmi, “The Accusation of Irjaʾ against Imam Abu Hanifah”, ilmgate.org
  12. Ṣaḥīḥ Muslim 121, ʿAmr b. al-ʿĀṣ on his deathbed, in Muslim's Ṣaḥīḥ: sunnah.com/muslim:121

Further reading

Six books to start with, chosen for a reader with no prior background. This is a different list from the sources above, which are there so the claims can be checked.

  • Wilferd Madelung, The Succession to Muhammad (Cambridge, 1997)The most rigorous reconstruction of the succession crisis from the earliest sources. Unusual among Western accounts in taking the case for ʿAlī seriously on its evidence.
  • Najam Haider, Shīʿī Islam: An Introduction (Cambridge, 2014)The best single starting point on Shiism. Organised around memory and ritual rather than a list of beliefs, and covers Zaydīs and Ismailis properly rather than as footnotes.
  • Jonathan A. C. Brown, Hadith (Oneworld, 2nd ed. 2017)How the hadith corpus was built, criticised and canonised. Read this if the isnād material here raised more questions than it answered.
  • Hugh Kennedy, The Prophet and the Age of the Caliphates (Routledge, 3rd ed. 2015)The political narrative the theology sits inside. Clear, sceptical and readable without prior background.
  • Fred M. Donner, Muhammad and the Believers (Harvard, 2010)Argues that the confessional boundaries hardened later than anyone assumed. Contested, and worth reading for the argument you will want to resist.
  • Marshall Hodgson, The Venture of Islam, vol. 1 (Chicago, 1974)Fifty years old and still unmatched in scope. Demanding prose; the payoff is a sense of the whole civilisation rather than a sequence of sects.
Prepared as a neutral reference. Where the traditions disagree, both positions are given in their own terms and no verdict is offered. Errors of fact are worth correcting; readings you disagree with are, in most cases, someone's sincere reading of the same text.
Cite this page

Siddiqui, M. “How Sunni and Shia Came to Be.” mohammadsiddiqui.com.

Part of a three-part series on the origins, anatomy and diffusion of the Sunni–Shia divergence. Where a causal story is scholarly inference rather than documented event-history, it is marked as such.
Part II · The House and the Schools → ↑ Top

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