When Muhammad founded the Islamic polity in Medina in 622 CE, he inaugurated more than a religion; he established a total system of governance. This was a state defined by revelation, where mosque and state were inseparable, and sacred authority was indistinguishable from political power. At its head stood the Caliph (khalīfat rasūl Allāh), divinely commanded as the Prophet's successor to lead the ummah. His multifaceted duty encompassed enforcing God’s law (Sharī‘a), protecting the Muslim community, waging jihad to expand Allah’s rule, and preserving the unity of Islam as a global order under God's sovereignty.
This fundamental model of fused religious and political authority, with divine law as the basis of public life, was the enduring structure passed through successive dynasties: the Rightly Guided Caliphs (al-Khulafā’ al-Rāshidūn), the Umayyads, and the Abbasids. Empires rose and fell, capitals shifted, and power changed hands, yet this system endured for centuries. The Caliphate, as Islam's political architecture, remained unbroken. Even the devastating Mongol sack of Baghdad in 1258, which killed Caliph al-Musta‘ṣim and leveled the Abbasid seat, could not erase the institution. Within years, the Abbasid Caliphate was symbolically restored in Cairo under the Mamluks, ensuring the continuity of its title and the legitimacy of the office, albeit stripped of its former might. This preservation was paramount in Islamic political doctrine, where appointing a Caliph is considered a communal obligation (fard kifayah) that the Muslim ummah must fulfill. Scholars like Al-Mawardi, Al-Juwayni, and Ibn Taymiyyah affirmed that the Muslim world could not exist a single day without a Caliph, given his indispensable role in implementing God’s law on earth.