The Banu Qurayza (Arabic: بني قريظة; بنو قريظة alternate spellings include Quraiza, Qurayzah, Quraytha, and the archaic Koreiza) were a Jewish tribe which lived in northern Arabia, at the oasis of Yathrib (presently known as Medina), until the 7th century. In February/March of 627 AD, their conflict with Muhammad led to a 25-day siege of Banu Qurayza ending in the tribe's surrender. The Banu Qurayza refused to submit to Muhammad's judgment and so asked the Auws, (also spelled Aws) tribe to intervene on their behalf. Muhammad not wanting to antagonize the Auws deferred the issue to them. The leaders of Banu Qurayza were gathered and were asked by the Auws what the punishment is for a traitor in their own religion. They bowed their heads and stated according to the Torah the punishment is death. So on the order of Sa'd ibn Mua'dth (leader of the Auws tribe), the men were executed, while the women and children were enslaved. There is much debate about the number executed with some estimating that between 400-900 men were beheaded, while the Sunni hadith simply state that all male members were killed, without specifying a figure, and one woman.
Jewish tribes reportedly arrived in Hijaz in the wake of the Jewish-Roman wars and introduced agriculture, putting them in a culturally, economically and politically dominant position. However, in the 5th century, the Banu Aws and the Banu Khazraj, two Arab tribes that had arrived from Yemen, gained dominance. When these two tribes became embroiled in conflict with each other, the Jewish tribes, now clients or allies of the Arabs, fought on different sides, the Qurayza siding with the Aws.
In 622, the Islamic prophet Muhammad arrived at Yathrib from Mecca and reportedly established a compact between the conflicting parties. While the city found itself at war with Muhammad's native Meccan tribe of the Quraysh, tensions between the growing numbers of Muslims and the Jewish communities mounted.
In 627, when the Quraysh and their allies besieged the city in the Battle of the Trench, the Qurayza entered into negotiations with the besiegers. Subsequently, the tribe was charged with treason and besieged by the Muslims commanded by Muhammad. The Banu Qurayza were overtaken and most of the men, apart from those who surrendered (many of whom converted to Islam in order to save their lives), were beheaded, while all the women and children were taken captive and enslaved. Some authors have challenged the veracity of this incident, arguing that it was exaggerated or invented.