Ubaydallah ibn al-Mahdi

Ubaydallah ibn Muhammad al-Mahdi (Arabic: عبيد الله بن محمد المهدي, romanized: ʿUbayd Allāh ibn Muḥammad al-Mahdī)^[1] (771–810/11) was an Abbasid prince. He was the son of al-Mahdi, the third caliph of the Abbasid Caliphate, and Raytah, daughter of the first Abbasid caliph Abu al-Abbas al-Saffah.^[2]

Ubaydallah ibn al-Mahdi عبيد الله بن محمد المهدي
Governor of Arminiya
In office	c. 788 – 791
Predecessor	Yazid ibn Mazyad al-Shaybani
Successor	Abd al-Qadir (791) then Al-Fadl ibn Yahya
Governor of Egypt
In office	795 – 795 (first term)
Predecessor	Abdallah ibn al-Musayyab
Successor	Musa ibn Isa
In office	796 – 797 (second term)
Predecessor	Musa ibn Isa
Successor	Isma'il ibn Salih
Born	771 Baghdad, Abbasid Caliphate
Died	810/11 Baghdad, Abbasid Caliphate, now Iraq
Burial	Baghdad
Names Ubaydallah ibn Muhammad al-Mahdi ibn Abdallah al-Mansur
Dynasty	Abbasid
Father	Al-Mahdi
Mother	Raytah
Religion	Islam

Life

In 761, the future caliph al-Mahdi married Raytah as his first wife after his return from Khurasan.^[3] She was the daughter of al-Saffah and his wife Umm Salamah, a Makhzumite.^[4] Raytah gave birth to two sons, Ubaydallah and Ali.^[3]

During the reign of his half-brother Harun al-Rashid (r. 786–809), Ubaydallah was appointed as governor of Arminiyah and the northwestern provinces in 788/9, succeeding Yazid ibn Mazyad al-Shaybani.^[5] He was later appointed to two brief stints as governor of Egypt, in 795 and 796.^[6]

In 810 or 811 Ubaydallah died in Baghdad. His nephew al-Amin led the prayers at his funeral.^[7]

Siblings

Ubaydallah was contemporary and related to several Abbasid caliphs, princes and princesses. He had total ten half-siblings and he had one full brother named Ali ibn Muhammad al-Mahdi.

No.	Abbasids	Relation
1	Musa al-Hadi	Half-brother
2	Harun al-Rashid	Half-brother
3	Abbasa bint al-Mahdi	Half-sister
4	Ali ibn al-Mahdi	Brother
5	Mansur ibn al-Mahdi	Half-brother
6	Aliyah bint al-Mahdi	Half-sister
7	Ulayya bint al-Mahdi	Half-sister
8	Abdallah ibn al-Mahdi	Half-brother
9	Ibrahim ibn al-Mahdi	Half-brother
10	Banuqa bint al-Mahdi	Half-sister
11	Isa ibn al-Mahdi[8]	Half-brother