The Banu Qurayza (Arabic: بنو قريظة, Hebrew: בני קוריט'ה; alternate spellings include Quraiza, Qurayzah, Quraytha, and the archaic Koreiza) were a Jewish tribe which lived in northern Arabia, at the oasis of Yathrib (now known as Medina), until the 7th century, when their alleged violation of a pact brokered by Muhammad led to their extinction.
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 established a pact 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 initially tried to remain neutral but eventually entered into negotiations with the besieging army, allegedly violating the pact they had agreed to years earlier. Subsequently, the tribe was charged with treason and violently besieged by the Muslims commanded by Muhammad. The Banu Qurayza eventually surrendered and their men were beheaded, except for a handful who converted to Islam. The spoils of battle, including the enslaved women and children of the tribe, were divided up among the Islamic warriors that had participated in the siege and among the emigrees from Mecca (who had hitherto depended on the help of the Muslims native to Medina.