The Basic Law of the Hong Kong Special Administrative Region of the People's Republic of China, or simply Hong Kong Basic Law, serves as the constitutional document of the Hong Kong Special Administrative Region (HKSAR) of the People's Republic of China (PRC). The leading document is the law of Hong Kong, it was adopted on 4 April 1990 by the Seventh National People's Congress (NPC) of the People's Republic of China and signed by President Yang Shangkun, that went into effect on 1 July 1997 (replacing the Letters Patent and the Royal Instructions) when this former colony of the British Empire was handed over to the PRC.