Ibn Sa'd was born in the year 784 CE (168 AH) and died in 845 CE (230 AH). He was a SunniMuslimscholar of Islam and an Arabian biographer, received his training in the tradition from Al-Waqidi and other celebrated teachers. He lived for the most part in Baghdad, and had the reputation of being both trustworthy and accurate in his writings, which, in consequence, were much used by later writers.
Ibn Sa`d was from Basra, Iraq, then lived in Baghdad. He is said to have died at the age of 62 in Baghdad and was buried in the cemetery of the Syrian gate.
The book of The Major Classes (Arabic: Kitab Tabaqat Al-Kubra) is a compendium of biographical information about famous Islamic personalities. This eight-volume work contains the lives of Muhammad, his Companions and Helpers, including those who fought at the Battle of Badr as a special class, and of the following generation, the Followers, who received their traditions from the Companions. Ibn Saad's authorship of this work is attested in a postscript to the book added by a later writer. In this notice he is described as a "client of al-Husayn ibn `Abdullah of the `Abbasid family".