To clarify this topic is about:
-The Sixteen States of Northern China following the collapse of Western Jin
-Eastern Jin's successors Southern Song, Southern Qi, Southern Liang and Southern Chen
-The "Northern Dynasties" including Northern Wei, West and Eastern Wei, Western Zhou and Eastern Qi
I've been reading about this period of Chinese history a whole lot recently and I find it very interesting. Some would contend that the sixteen (many barbarian) states that arose in North China were a part of a Dark Age in Chinese history. Similarly, Eastern Jin was largely unstable as well. However Buddhism spread throughout China and became prominent at this time. The various ethnic groups on the frontier also mingled with Han Chinese and both sides sort of adopted each other's customs. There were some ugly moments during this era including cities being sacked and genocides being committed (most famously Ran Min's campaigns against the Jie). On the other hand technological progress was still occuring and the spread of Buddhism could be seen as nearly (or perhaps just as) important as the philosophies that arose during the similarly anarchic Warring States period. Also one of the most important governmental policies in Chinese history, the equal fields system, was implemented by the Tuoba Xianbei state of Northern Wei.
I used to think of this era as just a period of little accomplishment and nothing but internecine warfare between the Han and Sui/Tang. Now I think it was an extremely formative period in Chinese history. Anybody else interested in this "medieval" chinese era?