The world's second-largest religion, arising from the revelations received by the Prophet Muhammad in seventh-century Arabia โ a tradition of radical monotheism, revealed law, prophetic example, and a rich diversity of branches, schools, and mystical currents that spans fourteen centuries.
Islam is rooted in the conviction that there is one God โ Allah โ and that the Prophet Muhammad (c. 570โ632 CE) is the final messenger in a long line of prophets including Abraham, Moses, and Jesus. The faith rests upon two primary sources: the Qur'an, understood as the direct word of God revealed to Muhammad, and the Sunnah, the body of prophetic practice and saying recorded in the Hadith literature.
The Five Pillars โ the declaration of faith (Shahada), ritual prayer (Salah), obligatory almsgiving (Zakat), fasting during Ramadan (Sawm), and pilgrimage to Mecca (Hajj) โ provide the structural framework of Muslim practice across all branches and traditions. These shared obligations create a profound unity across an otherwise extraordinarily diverse global community of roughly 1.8 billion people.
The early Muslim community rapidly expanded beyond Arabia into Persia, North Africa, Central Asia, and the Iberian Peninsula, absorbing and transforming an enormous diversity of cultural and intellectual traditions in the process. From this encounter emerged the great flowering of Islamic philosophy, science, jurisprudence, and mysticism that preserved and advanced classical knowledge through the European Dark Ages, producing figures of the stature of Avicenna, Averroes, and Al-Ghazali.
The question of legitimate leadership after the Prophet's death in 632 CE became the central fault line from which the major branches of Islam emerged โ a division that was simultaneously political, theological, and profoundly spiritual, and whose reverberations continue to shape the Muslim world today.
Three principal streams emerged from the early Muslim community, each with its own theology, jurisprudence, and spiritual lineage.
โ 85โ90% of Muslims worldwide
The largest branch, Sunni Islam holds that the Prophet's successors should be chosen by community consensus. Its defining emphasis is on the Sunnah โ the recorded example and practice of the Prophet โ as the binding guide for Muslim life.
Sunni jurisprudence is organised into four major schools of law (madhhabs), which differ in their legal methodology and interpretation whilst sharing the same core theological convictions:
โ 10โ15% of Muslims worldwide
Shia Islam holds that legitimate leadership of the Muslim community should have passed through the Prophet's family, beginning with his cousin and son-in-law Ali ibn Abi Talib. Shia theology places great weight on the role of the Imam โ a divinely guided figure whose authority is both spiritual and political.
The principal Shia branches are:
Kharijite lineage ยท Found mainly in Oman
Ibadi Islam descends from the early Kharijite movement โ one of the first divisions in Islamic history, which held that any Muslim of sufficient piety could lead the community, regardless of tribal or family descent. The Kharijites became notorious for extremism, but the Ibadis represent a distinct and far more moderate surviving branch of this lineage.
Ibadi theology is characterised by its emphasis on communal accountability, its rejection of both Sunni and Shia claims to exclusive legitimacy, and its independent legal and theological tradition. Today Ibadism is found primarily in Oman, where it has shaped a distinctive form of Islamic governance and scholarship for over a millennium.
Beyond the primary branches, several influential movements and interpretive traditions have shaped Islamic thought and practice across the centuries.
The mystical and contemplative dimension of Islam, Sufism (Tasawwuf) exists as a living stream within both Sunni and Shia communities rather than as a separate sect. Its central concern is ihsan โ worshipping God as though you see Him โ and the inner purification of the self as the path to direct knowledge of the Divine.
Through its tariqas (orders) โ Qadiriyya, Naqshbandiyya, Shadhiliyya, Mevlevi, and many others โ Sufism developed a rich tradition of poetry, music, sacred dance, and contemplative practice, producing masters of the stature of Rumi, Ibn Arabi, Rabia al-Adawiyya, and Al-Hallaj.
Explore Sufism โA reform movement within Sunni Islam advocating a return to the practices and beliefs of the Salaf โ the earliest generations of Muslims. Salafism holds that centuries of jurisprudential elaboration, folk practice, and mystical innovation have obscured the original simplicity and purity of the Prophet's community.
Salafism encompasses a wide spectrum of positions โ from quietist scholars who avoid political involvement, to activist reformers, to more militant tendencies. It has been particularly influential in the Arabian Peninsula, and its relationship with Wahhabism (the dominant interpretation in Saudi Arabia) is a matter of scholarly debate.
Founded in 1889 by Mirza Ghulam Ahmad in the Punjab region of British India, the Ahmadiyya movement holds distinctive beliefs about prophethood โ specifically, that Ahmad was a promised reformer and, in some sense, a prophet. Ahmadis consider themselves Muslim and follow Islamic practice; however, most Sunni and Shia scholars regard them as outside the bounds of mainstream Islam, a position enshrined in law in several Muslim-majority countries.
Despite facing significant persecution, the Ahmadiyya community has grown to tens of millions worldwide, with a notable emphasis on peaceful propagation, interfaith dialogue, and community service.
Quranists hold that the Qur'an alone is the sufficient and authoritative source of Islamic guidance, rejecting or significantly minimising the authority of the Hadith โ the recorded sayings and actions of the Prophet Muhammad. This position entails a radical rethinking of many traditional Islamic practices and legal rulings, since much of Islamic law (fiqh) is derived from Hadith literature rather than the Qur'an directly.
Quranism is a minority position and exists as a diverse intellectual movement rather than a unified denomination. Its practitioners range from rationalist modernisers to mystically inclined interpreters who find in the Qur'an alone an inexhaustible depth of spiritual meaning.
Tawhid โ the absolute unity of God โ is the theological bedrock upon which every branch of Islam stands, however different their expressions of that unity may be. For Sunni jurists, tawhid is expressed through rigorous adherence to divine law; for Shia theologians, through the spiritual authority of the Imam who interprets that law for each age; for Sufi mystics, through the direct experiential annihilation of the self in God; for Salafi reformers, through the purification of all additions that obscure the pristine divine command. The differences are real and historically significant, but they orbit a common gravitational centre.
The Arabic language and the Qur'an function as extraordinary forces for unity across this diversity. Unlike most scriptures, the Qur'an has never been liturgically translated โ prayers across the Muslim world are performed in the same Arabic text, the same words in the same order that have bound Muslim communities together across fourteen centuries of political upheaval, geographical dispersion, and theological controversy. The experience of millions of voices reciting the same words simultaneously during the five daily prayers, or during Ramadan's nightly tarawih, is one of the most remarkable expressions of collective spiritual practice in human history.
The Hajj and sacred geography maintain a physical and symbolic centre that no other world religion possesses to quite the same degree. Mecca โ and within it the Ka'ba, understood as the earthly counterpart of the divine throne โ draws nearly three million pilgrims annually from every nation, language, and social class, all dressed in identical white garments. The pilgrimage dissolves ordinary social distinctions and enacts, in the body, the theological conviction that all human beings stand equally before God.
Scholars whose work illuminates the breadth and depth of the Islamic tradition with rigour, sensitivity, and genuine scholarly brilliance.
1933โ ยท Philosopher & Scholar of Islamic Thought
Iranian-American philosopher and one of the foremost scholars of Islamic intellectual history, Sufism, and the perennial philosophy. Nasr spent decades at Harvard and George Washington University, producing works that explain Islamic spirituality to Western audiences without reducing it. His Ideals and Realities of Islam (1966) remains one of the clearest introductions to the tradition in English. His multivolume The Study Quran (2015) is the most comprehensive traditional commentary on the Qur'an available in English.
1922โ1968 ยท Historian of World Islam
American historian at the University of Chicago whose posthumously published The Venture of Islam (3 vols., 1974) remains the most ambitious and intellectually rigorous history of Islamic civilisation ever written in English. Hodgson coined the term "Islamicate" to describe the broader cultural world shaped by Islamic civilisation beyond its strictly religious sphere, and his structural analysis of Islamic history across its full fourteen-century arc set the standard for all subsequent scholarship.
1943โ ยท Scholar of Islamic Mysticism
American scholar and the foremost English-language authority on Ibn Arabi and the metaphysical tradition of Islamic mysticism. Chittick's translations and studies โ including The Sufi Path of Knowledge (1989) and The Self-Disclosure of God (1998) โ have made the dense speculative metaphysics of the greatest Sufi thinker accessible to a general scholarly audience. His Sufism: A Beginner's Guide (2000) offers a superb entry point for the newcomer.
1919โ1988 ยท Islamic Philosopher & Reformer
Pakistani-American scholar at the University of Chicago and one of the most rigorous and controversial Muslim reformist thinkers of the twentieth century. Rahman's Islam (1966) and Major Themes of the Qur'an (1980) argued for a historically contextualised reading of Islamic sources that could address the challenges of modernity without abandoning the tradition's core spiritual and ethical commitments. His work remains a touchstone for progressive Islamic scholarship.