When the Chinese communists took over Tibet in 1951, Bhutan closed its frontier with Tibet and sided with its powerful neighbor to the south. To offset the chance of Chinese encroachment, Bhutan began a modernization program. Land reform was accompanied by the abolition of slavery and serfdom and the separation of the judiciary from the executive branch of government. Mostly funded by India after China's invasion of Tibet in 1959, the modernization program also included the construction of roads linking the Indian plains with central Bhutan. An all-weather road was completed in 1962 between Thimphu and Phuntsholing, the overland gateway town on the southwest border with India. Dzongkha was made the national language during Jigme Dorji's reign. Additionally, development projects included establishing such institutions as a national museum in Paro and a national library, national archives, and national stadium, as well as buildings to house the National Assembly, the High Court (Thrimkhang Gongma), and other government entities in Thimphu. The position of gongzim, held since 1907 by the Dorji family, was upgraded in 1958 to lonchen (prime minister) and was still in the hands of the Dorji. Jigme Dorji Wangchuck's reforms, however, although lessening the authority of the absolute monarchy, also curbed the traditional decentralizatio of political authority among regional leaders and strengthened the role of the central government in economic and social programs.