Sunni and Shia
Origins, anatomy, diffusion. Three long reads that try to explain the divergence without taking a side, and that say plainly where the evidence runs out.
Origins, anatomy, diffusion. Three long reads that try to explain the divergence without taking a side, and that say plainly where the evidence runs out.
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.
The three parts
Each stands on its own. Read them in order if you want the argument to build; jump straight to whichever question brought you here if not.
How Sunni and Shia Came to Be
The succession question, the scriptural evidence read by both traditions in their own terms, and the timeline of a divergence that took three centuries to finish.
The House and the Schools
The genealogy from the Prophet ﷺ to living claimants, every school broken down by the method it actually uses, and an honest answer to the fidelity question.
How Islam Travelled
How each school reached the countries it holds today. A map of the madhhabs is a map of medieval states, caravan roads and monsoon winds, not of doctrine.
The Qur'an: What It Is, How It Came Down, and How It Was Kept
Revealed over twenty-three years, then compiled and preserved.
Read it →Muhammad ﷺ: A Life
Mecca to Medina from the sources, with a timeline and family tree.
Read it →The People Around Muhammad ﷺ: Companions, Wives and Family
Short sourced profiles, and where Sunni and Shia accounts differ.
Read it →The Five Pillars and the Six Articles of Faith
Their origins, set beside the Twelver roots and branches.
Read it →How Islam Came to Australia
From Makassan trepangers to Lakemba, and the schools each wave brought.
Read it →Islamic Schools of Thought: The Complete Tree
Every madhhab, creed and movement, with a timeline view.
Explore it →The Hadith Collections: A Complete Tree
Who compiled each major book, Sunni and Shia, and when.
Explore it →How this is written
Three commitments govern all three parts, and they are worth stating before you start.
Both sides in their own terms
Where the traditions read the same verse or hadith differently, both readings are given as their own scholars would state them, and no verdict is appended. Where one tradition rejects a report the other accepts, that is stated rather than smoothed over.
Sources labelled by provenance
A report from Ṣaḥīḥ al-Bukhārī is a Sunni canonical source.7 One from al-Kāfī is a Twelver canonical source.811 A date from al-Ṭabarī is third-century historiography with its own problems.12 Every hadith carries a collection and number you can check.10
The limits are marked
Contested dates say so. Figures that circulate widely but are weakly sourced are named as such and not repeated. Where a causal story is modern scholarly inference rather than documented event-history, the text says which it is. None of it is a fatwa: on any question of belief or practice, ask a qualified scholar of your own tradition.
Nobody at the Prophet’s funeral belonged to a sect
What existed in 632 was a political crisis, then a civil war, then a set of unresolved arguments about authority.4 Only across the following two to three centuries did those arguments harden into two traditions with their own hadith canons, legal systems, theologies and rituals.5679
Reading the schism backwards into 632 is the most common error in popular accounts, on every side. Said plainly, because these pages give both traditions their own terms everywhere else: this historicist framing is itself a frame, not the view from nowhere. Each tradition holds that its own position is what the Prophet ﷺ left and the other is the departure, and neither concedes the account below.
What is actually counted
One figure to set expectations before you read any percentage anywhere in this series, or anywhere else.
↔ Scroll the figure sideways
Sources
The works behind the few claims made on this page. Each part of the series carries its own, much longer, numbered list.
Demography
- Pew Research Center, Mapping the Global Muslim Population (7 October 2009): Sunni 87–90%, Shia 10–13%
- Pew, Sunni and Shia Muslims (2011)
- 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
How the traditions formed
- Wilferd Madelung, The Succession to Muhammad: A Study of the Early Caliphate (Cambridge University Press, 1997)
- Marshall G. S. Hodgson, The Venture of Islam, vol. 1: The Classical Age of Islam (University of Chicago Press, 1974)
- Christopher Melchert, The Formation of the Sunni Schools of Law, 9th–10th Centuries C.E. (Brill, 1997)
- Jonathan A. C. Brown, The Canonization of al-Bukhārī and Muslim (Brill, 2007)
- Moojan Momen, An Introduction to Shiʿi Islam: The History and Doctrines of Twelver Shiʿism (Yale University Press, 1985)
- Hossein Modarressi, Crisis and Consolidation in the Formative Period of Shiʿite Islam (Darwin Press, 1993)
Primary texts
- 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
- 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
- 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
Siddiqui, M. “Sunni and Shia: origins, anatomy, diffusion.” mohammadsiddiqui.com.
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