The Chinese dominions stretched into the heart of Central Asia and included the Khanate of Kokand, which paid tribute to Beijing. Outer Mongolia and Xinjiang did not become provinces of the Chinese empire, but rather were directly administered by the Qing dynasty. The fact that there was no provincial governor meant that the local rulers retained most of their powers and this special status also prevented emigration from the rest of China into the region. Persia also began to expand north, especially under the rule of Nadir Shah, who extended Persian dominion well past the Oxus. After his death, however, the Persian empire rapidly crumbled.