With the invasion of Tibet in 1950 and the subsequent Seventeen Point Agreement, the PRC asserted control over Tibet.
Tibet had been under Chinese Imperial control in the past, but had been independent since 1912
Also called the Agreement of the Central People's Government and the Local Government of Tibet on Measures for the Peaceful Liberation of Tibet
the document by which the delegates of the 14th Dalai Lama reached an agreement with the government of the newly-established PRC on affirming Chinese sovereignty over Tibet.
Chinese sources regard the document as a legal contract that was mutually welcomed by both governments and by the Tibetan people.
Tibetan sources generally consider it invalid, as having been reluctantly or unwillingly signed, under duress
In 1959, the Dalai Lama on his arrival in India after he fled Tibet repudiated the Agreement as having been "thrust upon Tibetan Government and people by the threat of arms.
By 1950 international recognition of the Communist government had increased considerably, but it was slowed by China's involvement in the Korean War.
In October 1950, sensing a threat to the industrial heartland in northeast China from the advancing United Nations forces in North Korea units of the PLA--calling themselves the Chinese People's Volunteers--crossed the YaluJiang ( ) River into North Korea in response to a North Korean request for aid
Almost simultaneously the PLA forces also marched into Xizang to reassert Chinese sovereignty
Xizang had been independent since the fall of the Qing dynasty in 1911.
In 1951 the UN declared China to be an aggressor in Korea and sanctioned a global embargo on the shipment of arms and war materiel to China.
This step foreclosed for the time being any possibility that the People's Republic might replace Nationalist China (Taiwan) as a member of the UN and as a veto-holding member of the UN Security Council
After China entered the Korean War, the initial moderation in Chinese domestic policies gave way to a massive campaign against the "enemies of the state," actual and potential.
These enemies consisted of "war criminals, traitors, bureaucratic capitalists, and counterrevolutionaries." The campaign was combined with party-sponsored trials attended by huge numbers of people.
The major targets in this drive were foreigners and Christian missionaries who were branded as United States agents at these mass trials.
The 1951-52 drive against political enemies was accompanied by land reform, which had actually begun under the Agrarian Reform Law of June 28, 1950.
The redistribution of land was accelerated, and a class struggle against landlords and wealthy peasants was launched.
An ideological reform campaign requiring self-criticisms and public confessions by university faculty members, scientists, and other professional workers was given wide publicity.
Artists and writers were soon the objects of similar treatment for failing to heed Mao's dictum that culture and literature must reflect the class interest of the working people