Final answer:
The People's Republic of China was established in 1949 when Mao Zedong's Communist Party won the civil war and took control of the mainland government.
Step-by-step explanation:
The People's Republic of China came into existence when Mao Zedong's Communist Party took control of the government following the civil war. After World War II, the civil war between the Communist forces led by Mao and the Nationalists led by Chiang Kai-shek resumed. Despite temporary cooperation during World War II, the rivalry intensified post-war. In 1949, after emerging victorious over the Nationalists, Mao declared the establishment of the PRC, marking the end of the last Chinese dynasty and dynastic rule. Despite the changes, the United States initially refused to recognize the new government, instead recognizing the Nationalist government which had fled to Taiwan as the legitimate Chinese government until the 1970s.