Eventually, the Aws and the Khazraj became hostile to each other. They had been fighting possibly for around a hundred years before 620 and at least since 570s. The Banu Nadir and the Banu Qurayza were allied with the Aws, while the Banu Qaynuqa sided with the Khazraj. There are reports of the constant conflict between Banu Qurayza and Banu Nadir, the two allies of Aws, yet the sources often refer to these two tribes as “brothers”. Aws and Khazraj and their Jewish allies fought a total of four wars. The last and bloodiest altercation was the Battle of Bu'ath, the outcome of which was inconclusive.