Kitab At-Tabaqat Al-Kabir by Abu Abdullah Muhammad ibn Sa d is one of the most important and earliest surviving collections of biographical details of the early Muslims, spanning just over the first two centuries of Islam.The scope of the work of Ibn Sa d covers the time of the Rashidun Khalifs, the Umayyads, and the Abbasids. This third volume of the Tabaqat (Volume III) deals with the Companions who were present at the Battle of Badr and with the Leaders of the Ansar who participated in the Pledge of Aqaba.