Birth and family life
On the eleventh of
Dhu al-Qi'dah, 148 AH (December 29, 765 CE), a son was born in the house of Imam Musa al-Kadhim (the seventh Imam of
Shia Islam) in
Medina. He was named Ali and titled al-Ridha, literally meaning in Arabic, "the contented", since it was believed that
Allah was contented with him. His
kunya (alternative name) was Abu'l Hasan, since he was the father of al-Hasan; the naming of a father after his son being a common practice in Arab culture. However, in the Shia sources he is commonly called Abu’l-Ḥasan al-Ṯānī (the second Abu'l Hasan), since his father,
Musa al-Kadhim, was also Abu'l Hasan (he was known as Abu’l-Ḥasan al-Awwal, meaning the first Abu'l Hasan). In keeping with his very high status amongst Shi'a, he has been given other honorific titles since, such as Saber, Vafi, Razi, Zakki amd Vali
Ali was born one month after the death of his grandfather,
Ja'far as-Sādiq, and brought up in Medina under the direction of his father.
 His mother, Najmah, was also a distinguished and pious lady. It is said that the boy al-Ridha required a great deal of milk, so that when his mother was asked whether her milk was sufficient, she answered, "it is not because my milk is not sufficient, but he wants it all the time, and consequently I am falling short in my prayers."
 She was originally a Nubian woman, She was purchased and freed by Bibi Hamidah Khatun, the wife of Imam
Ja'far al-Sadiq, who was also a Um Walad of Nubian origin. Imam Ali ibn Musa was said to be shadid udmah or aswad meaning he was very dark skinned or black complexion
. Bibi Hamidah was a notable Islamic scholar.
Disputes exist regarding the number of his offspring and their names. A group of scholars(Sunni) say that they were five sons and one daughter, and that they were: Muhammad al- Qani', al-Hasan, Ja’far, Ibrahim, al-Husayn, and 'Ayesha.
Sabt ibn al-Jawzi, in his work Tadhkiratul-Khawass("
تذکرۃ الخواص-Introduced eminence of the heirs of Muhammad The Prophet of Islam), says that the sons were only four, dropping the name of Husayn from the list.