The Federal Constitution of Malaysia (Malay: Perlembagaan Persekutuan Malaysia), which came into force in 1957 as the Constitution of the Federation of Malaya and was amended in 1963 to form the Constitution of Malaysia, is the supreme law of Malaysia and contains a total of 183 articles. It is a written legal document influenced by two previous documents, the Federation of Malaya Agreement 1948 and the Independence Constitution of 1957. The Federation was initially called the Federation of Malaya (Malay: Persekutuan Tanah Melayu) and it adopted its present name, Malaysia, when the states of Sabah, Sarawak and Singapore (now independent) became part of the Federation. The Constitution establishes the Federation as a constitutional monarchy, having the Yang di-Pertuan Agong as the Head of State with largely ceremonial roles. It provides for the establishment and organisation of three main branches of the government: the bicameral legislative branch called the Parliament, which consists of the House of Representatives (Dewan Rakyat) and the Senate (Dewan Negara); the executive branch led by the Prime Minister and his Cabinet Ministers and the judicial branch headed by the Federal Court.