Answer:
The territorial dispute over Taiwan originated in 1949 when the Chinese people fled to Taiwan due to the complete control of Communists in Mainland China.
Step-by-step explanation:
The event happened after the "Chinese Civil War," a war between the Kuomintang and the Communist Party of China (CPR). This resulted to many Chinese people fleeing from Southern China to Taiwan in order to prevent the advances of the Communist Party. This was also a sign of retreat from the war.
Moving to Taiwan from China took 4 months and this was meant to be a temporary solution rather than being permanent. However, the plan could not be realized thus, resulting to many Chinese people living in Taiwan until today.
So, this led to the controversial issue that Taiwan is, somehow, part of China. In connection with this, territorial disputes arose whether Taiwan should be unified with Mainland China.