Umar ibn Abd al-Aziz (c. 682 - February, 720 (Arabic: عمر بن عبد العزيز) was an Umayyad caliph who ruled from 717 to 720. Unlike previous Umayyad caliphs, he was not a hereditary successor to the former caliph, but was appointed. But he was also a cousin of the former caliph, being the son of Abd al-Malik's younger brother Abd al-Aziz.

His mother was Umm Asim bint Asim and his father was Abd al-Aziz, the governor of Egypt and younger brother of caliph Abd al-Malik. Umar was a great-grandson of the second Rightly Guided Caliph (a title Shia muslims do not apply to the first three) Umar ibn al-Khattab, whom the Sunnis regard as one of the Prophet's closest and most prominent companions.

Umar was born around 682. Some traditions state that he was born in Medina while others claim that he was born in Egypt.

According to a Sunni Muslim tradition, Umar's lineage to Umar ibn al Khattab stems from a famous event during the second Caliph's rule. During one of his frequent disguised journeys to survey the condition of his people, Umar overheard a milkmaid refusing to obey her mother's orders to sell adulterated milk. He sent an officer to purchase milk from the girl the next day and learned that she had kept her resolve; the milk was unadultered. Umar summoned the girl and her mother to his court and told them what he had heard. As a reward, he offered to marry the girl to his son Asim. She accepted, and from this union was born a girl that would in due course become the mother of Umar ibn Abd al-Aziz.

Umar would grow up in Medina and live there until the death of his father, after which he was summoned to Damascus by Abd al-Malik and married to his daughter Fatima. His father-in-law would die soon after, and he would serve as governor of Medina under his cousin Al-Walid I.

Unlike most rulers of that era, Umar formed a council with which he administered the province. His time in Medina was so notable that official grievances sent to Damascus all but ceased. In addition, many people emigrated to Medina from Iraq seeking refuge from their harsh governor, Al-Hajjaj bin Yousef. This angered Al-Hajjaj, and he pressed al-Walid to remove Umar. Much to the dismay of the people of Medina, al-Walid bowed to Hajjaj's pressure and dismissed Umar from his post. By this time, Umar had developed an impeccable reputation across the Islamic empire.

Umar continued to live in Medina through the remainder of al-Walid's reign and that of Walid's brother Suleiman. Suleiman, who was Umar's cousin and had always admired him, ignored his own brothers and son when it came time to appoint his successor and instead nominated Umar. Umar reluctantly accepted the position after trying unsuccessfully to dissuade Suleiman, and he approached it unlike any other Ummayad caliph before him.

Umar was extremely pious and disdainful of worldly luxuries. He preferred simplicity to the extravagance that had become a hallmark of the Umayyad lifestyle, depositing all assets and finery meant for the caliph into the public treasury. He abandoned the caliphal palace to the family of Suleiman and instead preferred to live in modest dwellings. He wore rough linens instead of royal robes, and often went unrecognized.

According to a Muslim tradition, a female visitor once came to Umar's house seeking charity and saw a raggedly-dressed man patching holes in the building's walls. Assuming that the man was a servant of the caliph, she asked Umar's wife, "Don't you fear God? Why don't you veil in the presence of this man?" The woman was shocked to learn that the "servant" was in fact the caliph himself.

Though he had the people's overwhelming support, he publicly encouraged them to elect someone else if they were not satisfied with him (an offer no one ever took him up on). Umar confiscated the estates seized by Ummayad officials and redistributed them to the people, while making it a personal goal to attend to the needs of every person in his empire. Fearful of being tempted into bribery, he rarely accepted gifts, and when he did he promptly deposited them in the public treasury. He even pressured his own wife--who had been daughter, sister and wife to three caliphs in their turn--to donate her jewelry to the public treasury.

At one point he almost ordered the Great Umayyad Mosque in Damascus to be stripped of its precious stones and expensive fixtures in favor of the treasury but he desisted on learning that the Mosque was a source of envy to his Byzantine rivals in Constantinople. These moves made him unpopular with the Umayyad court, but endeared him to the masses, so much so that the court could not move against him in the open.

In an effort to bring the empire into greater conformity with the standards set by Muhammad, Umar made a number of important religious reforms. He abolished the long-standing Umayyad and Khawaarij custom of cursing Ali ibn Abi Talib(the fourth Caliph), instituted by Muawiyah ibn Abu Sufiyan, at the end of Friday sermons and ordered the following Qu'ranic verse be recited instead:

- Surely God enjoins justice, doing of good and giving to kinsfolk

In addition, Umar was keen to enforce the Sharia, pushing to end drinking and bathhouses where men and women would mix freely. He continued the welfare programs of the last few Umayyad caliphs, expanding them and including special programs for orphans and the destitute. He would also abolish the Jizya tax for converts to Islam, who were former dhimmis, who used to be taxed even after they had converted under other Umayyad rulers.

Generally, Umar II is credited with having ordered the first collection of hadith material in an official manner, fearing that some of it might be lost. Abu Bakr ibn Muhammad ibn Hazm and Ibn Shihab al-Zuhri, are among those who compiled hadiths at `Umar II’s behest. .

Though Umar did not place as much an emphasis on expanding the Empire's borders as his predecessors had, he was not passive. Muhammad ibn Jarir al-Tabari states that he sent Ibn Hatim ibn al-Nu'man to repel Turks invading Azerbaijan (v. 24 pp. 74-75). He faced Kharijite uprising and preferred negotiations to armed conflict, personally holding talks with two Kharijite envoys shortly before his death (v. 24, p. 77-78). He recalled the troops besieging Constantinople (p. 74). These were led by his cousin Maslama. This Second Arab siege of Constantinople had seen Muslim troops courageously fighting Byzantines and Slavs, though at some cost.

His reforms in favor of the people greatly angered the nobility of the Umayyads, and they would eventually bribe a servant into poisoning his food. Umar learned of this on his death bed and pardoned the culprit, collecting the punitive payments he was entitled to under Islamic Law but depositing them in the public treasury. He died in February, 720, probably the 10th and probably forty years old (v. 24, pp. 91-92) in Aleppo.

He was succeeded by his cousin Yazid II.

Rulers usually appoint people to watch over their subjects. I appoint you a watcher over me and my behaviour. If you find me at fault in word or action guide me and stop me from doing it.

-Umar Ibn Abd al-Aziz

While Umar's reign was very short, he is very highly regarded in the Shi'a and Sunni Muslim memory.

He is considered one of the finest rulers in Muslim History, second only to the Four Rightly Guided Caliphs. In fact, in some circles, he is affectionately referred to as the Fifth and last Rightly Guided Caliph.

stated :

A [[Mujaddid

He is regarded by Shi'a Muslims as having only reformed to some degree the 'Umayyad policies in order to consolidate his own rule and save the Umayyad Dynasty from eradication.

Muhammad ibn Jarir al-Tabari v. 24 "The Empire in Transition," transl. David Stephan Powers, SUNY, Albany, 1989.