Immigration to Bhutan has an extensive history and has become one of the country's most contentious social, political, and legal issues. Since the twentieth century, Bhutanese immigration and citizenship laws have been promulgated as acts of the royal government, often by decree of the Druk Gyalpo on advice of the rest of government. Immigration policy and procedure are implemented by the Lhengye Zhungtshog (Council of Ministers) Ministry of Home and Cultural Affairs, Department of Immigration. Bhutan's first modern laws regarding immigration and citizenship were the Bhutanese Citizenship Act 1958 and subsequent amendments in 1977. The 1958 Act was superseded by the Bhutanese Citizenship Act 1985, which was then supplemented by a further Immigration Act in 2007. The Constitution of 2008 included some changes in Bhutan's immigration laws, policy, and procedure, however prior law not inconsistent with the 2008 Constitution remained intact. Bhutan's modern citizenship laws and policies reinforce the institution of the Bhutanese monarchy, require familiarity and adherence to Ngalop social norms, and reflect the social impact of the most recent immigrant groups.