徐振 (pinyin Xú Zhèn) was born on 27 February 1891 in Macau, although his parents, Wing Pao and Soo Pan, were originally from Guangdong Province. At that time in Chinese history, many port cities were under significant or even total foreign control. The Chinese treaty port system ceded control of specific zones in coastal cities to foreign powers – as in the American/British and French concessions of Shanghai – or in the cases of Hong Kong and Macau, complete colonial administration. These areas functioned somewhere on the spectrum from Vatican City to the former Panama Canal Zone in their laws and regulations on movement to and from the area. Since Macau was under Portuguese colonial administration, 徐振 was born a Portuguese citizen, although he was ethnically Chinese.