<P> In the early 5th century, China entered a period known as the Northern and Southern dynasties, in which parallel regimes ruled the northern and southern halves of the country . In the south, the Eastern Jin gave way to the Liu Song, Southern Qi, Liang and finally Chen . Each of these Southern dynasties were led by Han Chinese ruling families and used Jiankang (modern Nanjing) as the capital . They held off attacks from the north and preserved many aspects of Chinese civilization, while northern barbarian regimes began to sinify . </P> <P> In the north, the last of the Sixteen Kingdoms was extinguished in 439 by the Northern Wei, a kingdom founded by the Xianbei, a nomadic people who unified northern China . The Northern Wei eventually split into the Eastern and Western Wei, which then became the Northern Qi and Northern Zhou . These regimes were dominated by Xianbei or Han Chinese who had married into Xianbei families . During this period most Xianbei people adopted Han surnames, eventually leading to complete assimilation into the Han . </P> <P> Despite the division of the country, Buddhism spread throughout the land . In southern China, fierce debates about whether Buddhism should be allowed were held frequently by the royal court and nobles . By the end of the era, Buddhists and Taoists had become much more tolerant of each other . </P> <P> The short - lived Sui dynasty was a pivotal period in Chinese history . Founded by Emperor Wen in 581 in succession of the Northern Zhou, the Sui went on to conquer the Southern Chen in 589 to reunify China, ending three centuries of political division . The Sui pioneered many new institutions, including the government system of Three Departments and Six Ministries, imperial examinations for selecting officials from commoners, while improved on the systems of fubing system of the army conscription and the Equal - field system of land distributions . These policies, which were adopted by later dynasties, brought enormous population growth, and amassed excessive wealth to the state . Standardized coinage were enforced throughout the unified empire . Buddhism took root as a prominent religion and were supported officially . Sui China was known for its numerous mega-construction projects . Intended for grains shipment and transporting troops, the Grand Canal was constructed, linking the capitals Daxing (Chang'an) and Luoyang to the wealthy southeast region, and in another route, to the northeast border . The Great Wall was also expanded, while series of military conquests and diplomatic maneuvers further pacified its borders . However, the massive invasions of the Korean Peninsula during the Goguryeo--Sui War failed disastrously, triggering widespread revolts that led to the fall of the dynasty . </P>

When did the chinese civilization start and end