The himalayan Nation of Nepal borders northern India in the south, east and west. During British rule in India, Nepal's ties with the British government were governed by the 1816 Treaty of Sugauli that was replaced by the 1923 "Treaty of perpetual peace and friendship" or Nepal–Britain Treaty of 1923. After the independence of India in 1947, the two nations sought to forge close strategic, commercial and cultural relations. The rise of Communist China in 1949 and the subsequent invasion of Tibet heightened security concerns in both India and Nepal. India had maintained good relations with Tibet, but the Rana rulers of Nepal feared that China would support the Communist Party of Nepal and sponsor a communist revolution that would overthrow their autocratic regime.