Banners were first used during the Qing Dynasty, which organized the Mongols into banners except those who belonged to the Mongol Eight Banners. Each banner had sumun as nominal subdivisions, which also means arrow. In Inner Mongolia, several banners made up a league. In the rest, including Outer Mongolia, northern Xinjiang and Qinghai, ayimagh was the largest administrative division. While it restricted the Mongols from crossing banner borders, the dynasty protected Mongolia from population pressure from China proper.
InnerMongolia is contrasted with Outer Mongolia, which was used by the Republic of China and previous governments to refer to what is covered today by the independent nation of Mongolia plus Russia' Republic of Tuva.
InnerMongolia borders, from east to west, the provinces of Heilongjiang, Jilin, Liaoning, Hebei, Shanxi, Shaanxi, Ningxia Hui Autonomous Region, and Gansu, while to the north it borders Mongolia and Russia.
Present-day eastern InnerMongolia, then part of Manchuria, came under the control of the Japanese puppet state Manchukuo in 1931, and was administered thus until the end of the war in 1945.
Mongolia's external policies, however, were founded on those of the Soviet Union, and relations with China, always influenced by suspicions over real or imaginary claims by China to "lost territories," faltered in the wake of the Sino-Soviet rift that developed in the late 1950s.
Mongolia - Khubilai Khan and the Yuan Dynasty, 1261-1368
Mongolia's general foreign policy line was based on strong ties with the Soviet Union, "the reliable pillar of [Mongolia's] independence and prosperity" according to the party line.