Wu Hu
Following the War of the Eight Princes, the barbarian tribes in north China, under the collective Wu Hu, saw an opportunity to take advantage of the chaos in China. Their forces, under Liu Yuan, revolted against the Jin in 304 CE. Although Jin forces fought hard to contain Wu Hu uprising, they suffered a major defeat in 310 CE that wiped out an army of over 100,000 troops, and afterwards could not hold north China. In 311 CE, the Wu Hu sacked the Jin capital, Luoyang, killing over 30,000 people, and Jin's secondary capital, Chang'an, was also captured in 316 CE.