Despite the cession of Macau to Portugal in 1557 and Hong Kong to Britain in 1842, the ethnic Chinese population of the two territories largely originated from the 19th and 20th century immigration from Guangzhou and surrounding areas, making Cantonese the predominant Chinese language in the territories. On the mainland, Cantonese continued to serve as the "lingua franca" of Guangdong and Guangxi provinces even after Mandarin was made the official language of the government by the Qing dynasty in the early 1900s. Cantonese remained a dominant and influential language in southeastern China until the establishment of the People's Republic of China in 1949 and its promotion of Standard Mandarin Chinese as the sole official language of the nation throughout the last half of the 20th century, although its influence still remains strong within the region.