The People’s Republic of China (PRC) was established after the communist forces prevailed in the 1947–1949 Chinese Civil War. The nationalist government fled to Taiwan and, due to Cold War dynamics that labeled the PRC a revolutionary threat to the international order, it was recognized by the UN as China’s sole representative. This chapter looks at how sovereignty was understood and pragmatically articulated in the early decades of the PRC. National reunification, the frontier question, and the full abolition of all the privileges of Western imperialism and the unequal treaties continued to be among the communists’ most important prerogatives. If in its foreign policy it upheld the same principles of the republican period, namely equality, mutual benefit, respect for sovereignty, and territorial integrity, it had to resocialize with other countries according to its new Marxist-Leninist identity.