Al-Mansur (Abu Ja'far al-Mansur)

Abu Ja'far Abdallah ibn Muhammad al-Mansur, celebrated by his regnal title Al-Mansur ('the Victorious'), was the second Abbasid Caliph and the true organizational founder of the Abbasid dynasty. Governing from 754 to 775 CE, Al-Mansur inherited a turbulent state following the Abbasid Revolution that had overthrown the Umayyads, consolidating authority through ruthless administrative efficiency, fiscal thrift, and state security.

Al-Mansur's greatest historical monument was the founding of Baghdad. Seeking a new imperial capital at the strategic crossroads of Mesopotamian irrigation canals and Silk Road trade routes, Al-Mansur laid the foundation stone on July 30, 762 CE. Designed as a perfect geometric Round City (Madinat al-Salam, the 'City of Peace') enclosed within double concentric brick walls with four equidistant gates, Baghdad grew into the largest, wealthiest, and most cosmopolitan metropolis on Earth. A patron of scholars, Al-Mansur established the palace translation movement, commissioning translations of Sanskrit mathematical texts (introducing zero and Hindu-Arabic numerals) and Greek astronomical treatises, laying the groundwork for the Islamic Golden Age.