Arwā bint Manṣūr al-Ḥimyarī (Arabic: أروى بنت منصور الحميرى) also known as Umm Mūsā (Arabic: ام موسى) was the famous principal wife of Abbasid caliph al-Mansur (r. 754–775) and mother of third Abbasid caliph al-Mahdi.
Arwa was the daughter of Mansur al-Himyari, a descendant of the Banu Himyar tribe, whose ancestors ruled Yemen in pre-Islamic times (110 BCE–525 CE).
[1] She married Abu Ja'far Abdallah ibn Muhammad, the future Abbasid caliph al-Mansur.
Al-Mansur tried to annul this agreement several times, but Arwa always managed to convince the judges not to do that.
When her brother-in-law, al-Saffah, died after a five-year reign, her husband al-Mansur became caliph and held on to power for nearly 22 years, from 754 to 775.