The Banà « Aws ( , "Sons of Aws") or simply Aws (, also romanized as Aus) was one of the two main Arab tribes of Medina. The other was the Khazraj. Both were descendants of Thaûlaba bin ûAmr, the son of King Muzayqiya, who ruled parts of Yemen in the 2nd century and was the leader of the Azd tribe.
Aws and Khazraj were known as Banà « Qayla ( ) in the pre-Islamic era. After the Hijra, the journey of the Islamic prophet Muhammad from Mecca to Medina, both tribes became known as Ansar ("The Helpers").
The word al-Aws means "the gift", probably a contraction for Aws ManÃÂt (, "the gift of ManÃÂt"). The name was changed in Islamic times to Aws AllÃÂh ().
About AD 300, Thaûlaba bin ûAmr, grand father of al-Aws, separated from his tribe and settled in Yathrib (Medina), which was then controlled by Jewish clans, and the Banu Qayla were subordinate to the Jews for some time, until MÃÂlik bin AjlÃÂn of Khazraj asserts independence of the Jews so Aws and Khazraj obtained a share of palm trees and strongholds. Thus, about the 5th century, the Banu Qayla took control of Yathrib, and Jews retired into the background for about a century.
During the period before the Hijra, Abu Qays al-Aslat of the clan of WÃÂüil, the leader of Aws, gave away the leadership to Ḥuá¸Âayr bin SimÃÂk of ûAbd al-Ashhal. After a serious defeat, ûAbd al-Ashhal and áºÂafar were withdrawn from Yathrib. The opposing leader, ûAmr bin NuûmÃÂn, of the Khazrajite clan of BayÃÂá¸Âa, drove the Jewish tribes of Banu Qurayza and Banu Nadir into alliance of the two. Nomads of Muzayna joined them too. Most of the Khazraj except ûAbd AllÃÂh bin Ubayy and another Khazraj leader, as well as the Jewish tribe Banà « QaynuqÃÂû and the nomadic Juhayna and Ashjaû, supported âÂÂAmr bin NuâÂÂmÃÂn. The Awsite clan of ḤÃÂritha remained neutral. Then, in about 617, the Yawm al-Bu'ath began: the Aws forced back at first but finally defeated their opponents. The leaders of both sides were killed.
Shi'a sources say they were Jews, But a Jewish source says that they and the Banu Khazraj were Arab tribes from Yemen who came to Medina in the fourth century. The Jewish source says that the two tribes took the power of Medina from the Jews in the 5th century by "calling in outside assistance and treacherously massacring at a banquet".
A Shi'a source says that they had been fighting for 120 years and were enemies. The Jewish source states that they went to war against each other in the Battle of Bu'ath a few years before the Islamic prophet Muhammad migrated to Medina.
There were many Jewish tribes in Medina: Banu Nadir, Banu Qurayza, Banu Qaynuqa and 9 others, if not more, as referenced in the Medina mutual peace and security treaty (although Qaynuqa, Nadir, and Qurayza aren't named in the treaty). Some where familial clans of larger non-Jewish Arab tribes (e.g. Banu Aws, whom took initiative to invite and provide refuge to Mohammad and his first followers thus earning 'Al-Ansar' title) while some others had non-Jewish familial clans within their tribes, and others were purely Jewish.
In the battle of Yawm al-Bu'ath, the tribes of Banu Nadir and Banu Qurayza fought with Banu Aws, while the tribe of Banu Qaynuqa allied with Banu Khazraj. The latter were defeated after a long and desperate battle.
The Banu Aws were included in the Constitution of Medina as allies to the Muslims, "one nation/community with the Believers". Then, Banu Aws and others became known as the Ansar.
The Banu Qurayza were a Jewish tribe who lived in Medina. The tribe's men, apart from a few who converted to Islam, were sentenced to death in 627 in retaliation for Banu Qurayza treachery and subversion in aiding the Meccan pagan enemies who had launched a ferocious attack on Madinah, in order to eliminate the Muslims and their allies during the Battle of the Trench.
Since the Banu Qurayza had been an ally of the Banu Aus during the Battle of Bu'ath, they choose Sa'ad ibn Mua'dh, the chief of the Banu Aus as their judge. He condemned the men to death and the women and children to slavery. Sa'ad ibn Mua'dh himself died shortly after the event from injuries that he had received during the Battle of the Trench.