Hong Kong became a part of China in 1997 following the principle of 'one country, two systems’. Which is a constitutional principle formulated by Deng Xiaoping, the Paramount Leader of the People's Republic of China (PRC), for the reunification of China during the early 1980s. He suggested that there would be only one China, but distinct Chinese regions such as Hong Kong and Macau could retain their own economic and administrative systems, while the rest of China uses socialism with Chinese characteristics system. Under the principle, each of the two regions could continue to have its own governmental system, legal, economic and financial affairs, including trade relations with foreign countries. Hong Kong was a colony of the United Kingdom, ruled by a governor for 156 years until 1997, when it was returned to Chinese sovereignty.