Umar ibn Abd al-Aziz

Umar ibn Abd al-Aziz ibn Marwan (Arabic: عُمَر بْن عَبْد الْعَزِيز بْن مَرْوَان, romanized: ʿUmar ibn ʿAbd al-ʿAzīz ibn Marwān; c. 680 – February 720) was the eighth Umayyad caliph, ruling from 717 until his death in 720. He is credited to have instituted significant reforms to the Umayyad central government, by making it much more efficient and egalitarian. His rulership is marked by the first official collection of hadiths and the mandated universal education to the populace.

He dispatched emissaries to China and Tibet, inviting their rulers to accept Islam. It was during his three-year reign that Islam was accepted by huge segments of the populations of Persia and Egypt. He also ordered the withdrawal of the Muslim forces in various fronts such as in Constantinople, Central Asia and Septimania. However despite this, his reign witnessed the Umayyads gaining many new territories in the Iberian Peninsula.

Umar is regarded by many Sunni scholars as the first mujaddid and is sometimes referred to as the "fifth rightly guided caliph" due to his reputation for just governance. Some Sunni scholars consider Hasan ibn Ali’s brief caliphate (661) as part of his father Ali ibn Abi Talib’s rule, citing a hadith that describes the rightly guided caliphate as lasting thirty years. Umar was also honorifically called Umar al-Thani (Umar II) after his great-grandfather, Caliph Umar ibn al-Khattab (r. 634–644).