The Manchus were 
not of Chinese origin and most Chinese protested their rule. It was soon apparent that if the Manchus wanted to keep their power they would have to continue the Chinese traditions. This was not a difficult task as the Manchus assimilated much of the Chinese culture on their rise to power. They continued the religious rituals over which the emperor presided, and kept all of the Confucian court practices that defined Chinese dynastic rule. With this the Qing dynasty was established.
The Manchus did not want to change the civil service system which had been working for thousands of years. The system continued using tests to determine the best-qualified person for the post. Although Han Chinese were barred from holding high offices, the Chinese still outnumbered the Manchus in office holdings outside the capital (except military positions). Neo-Confucian principles of obedience to the ruler by the ruled remained as the official state philosophy. Huge historical projects were started to officially record history and ancient texts. These projects were a tremendous success and resulted in a cultural renewal of China.
Although trying to continue the Chinese tradition, the Manchus were afraid to lose their own culture. Steps were taken to prevent complete cultural diffusion. Han Chinese were not allowed to move into the Manchu home land, Manchus could not go into trade or manual labor, and intermarriages were strictly forbidden. In addition, a dual appointment was used in government posts. A Chinese person would do all the technical and paper work while the Manchu would ensure Han loyalty to the Qing dynasty.
The Manchus were determined to keep their rule. Looking back at past dynasties they could see that downfall came from either rebellion or invasion. With steps taken to keep Han Chinese from holding high offices, and otherwise kept from power. The Manchus concentrated on preventing invasion. Their choice of defense was to attack. By the end of the seventeenth century the Manchus have conquered all of outer Mongolia. By the middle of the eighteenth century all of central Asia and Tibet fell under Qing rule. The Empire has gotten bigger than ever before. Soon Taiwan where anti-Manchu movements still raged on also came under Empirical rule. China proper was definitely safe from invasion, while the conquered nations paid tribute to the flourishing Qing dynasty.
The Qing dynasty was as stable as any before it had ever hoped to achieve. Their downfall though, came in a different manner. The defeat came by sea in the southern port cities and then spread like a plague infecting every part of the Empire. Westerners had discovered the wonders of China, and starting from the seventeenth century started to arrive in great numbers. Western traders looking for quick profits, missionaries looking to convert the "heathen folk", as well as soldiers of fortune seeking to exploit the "new" land. The rulers of the Empire did not know how to respond to these new problems. The rulers did not judge the effect of these outsiders on the infrastructure of their society. The rulers did not respond in time and with the proper measures. Therefore, due to this foreign invasion, the great Chinese Empire collapsed in February 1912.