April 1888. Articles II and III stated: II. China confirms, in its entirety, the second Article of the Protocol of Lisbon, relating to the perpetual occupation and government of Macao by Portugal. III. Portugal confirms, in its entirety, the third Article of the Protocol of Lisbon, relating to the engagement never to alienate Macao without previous agreement with China. According to the Portuguese interpretation, sovereignty over Macau was surrendered to Portugal. In the Chinese interpretation, however, only administrative rights were transferred. Aftermath After December 1887, issues related to rent payments and the presence of a Chinese custom house or resident mandarin in Macau became irrelevant outside of academic interest. The early 20th century marked a new era for both countries, with Portugal's 1910 and China's 1911 republican revolutions establishing new governments. A growing nationalist movement in China voiced disapproval of the treaty and questioned its validity. These contentions manifested themselves in the unresolved topic of Macau's border demarcation. Although the Nationalist (Kuomintang) government in China vowed to abrogate the "unequal treaties", Macau's status remained unchanged. The 1928 Sino-Portuguese Treaty of Friendship and Trade reaffirmed Portuguese administration over Macau. In 1945, after the end of extraterritorial rights in China, the Nationalists called for the liquidation of foreign control over Hong Kong and Macau, but they were too preoccupied in the Chinese Civil War with the Communists to fulfil their goals of a "rights recovery" campaign. After the 1974 Revolution in Portugal, a new decolonisation policy paved the way for Macau's retrocession to the People's Republic of China (PRC). Portugal offered to withdraw from Macau in late 1974, but China declined the offer in favour of a later time because it sought to preserve international and local confidence in Hong Kong, which was still under British rule, as well as because it prioritised the reunification of Taiwan. In January 1975, Portugal recognised the PRC as the sole legitimate government of China and ended ties with the Nationalists in Taipei. In 1976, Portugal unilaterally changed the legal designation of Macau from a "colony" to "territory under Portuguese administration". In 1987, the Sino-Portuguese Joint Declaration was signed and Macau became a "Chinese territory under Portuguese administration". On 20 December 1999—two years after the handover of Hong Kong—Macau was returned to Chinese rule. A copy of the treaty is kept by the Portuguese government while another copy is kept by the Ministry of Foreign Affairs