Answer
The independence of the Cheng Han and Han Zhao dynasties occurred from the Western Jin dynasty. The Cheng Han dynasty was founded in 304 by Liu Yuan, a Xiongnu nobleman. He was initially a vassal of the Western Jin dynasty, but he declared himself emperor in 304 and established the Cheng Han dynasty. The Han Zhao dynasty was founded in 304 by Liu Cong, another Xiongnu nobleman.