Chinese Youth Party member and modern Chinese historian Shen Yun-lung (沈雲龍), when he was teaching in the 1960s, always warned students that they could not believe anything written in history books after 1919 and the May Fourth Movement, and that he could not talk about anything that happened afterward.
The statement has two meanings. First, during the Martial Law era there was no academic freedom or freedom of expression; second, any analysis of important historical events after the May Fourth Movement — including the establishment of the Chinese Communist Party (CCP), the War of Resistance Against Japan and the Chinese Civil War — were deliberate fabrications and acts of obscurantism by the government.