The Qing Dynasty was founded not by the Han Chinese who form the majority of the Chinese population, but the Manchus, who are today an ethnic minority of China. The Manchus were keenly aware of their minority status and during the early eras of their reign, they implemented a strict policy of racial segregation between the Manchus and Han Chinese. This ethnic segregation had cultural and economic reasons: intermarriage was forbidden to keep up the Manchurian heritage and minimize sinicization. Han Chinese and Mongols were banned from settling in Manchuria. The Qing Dynasty started colonizing Manchuria with Han Chinese later on in the dynasty's rule, but the Manchu area was still separated from modern-day Inner Mongolia by the Outer Willow Palisade, which kept the Manchu and the Mongols in the area separate.
The policy of segregation applied directly to the banner garrisons, most of which occupied a separate walled zone within the cities in which they were stationed. While the Manchus followed the governmental structure of the preceding Ming dynasty, their ethnic policy dictated that appointments were split between Manchu noblemen and Han Chinese officials who had passed the highest levels of the state examinations, and because of the small number of Manchus, this insured that a large fraction of them would be government officials.