The observation of 31 August as Malaysia's national day is the cause of some controversy, due to calls to prioritize the celebration of "Hari Malaysia" (Malaysia Day) on 16 September instead. "Hari Malaysia" commemorates the formation of Malaysia in 1963, when 4 intities called North Borneo, Sarawak, Singapore and Malaya federation to form Malaysia. Some, especially people from East Malaysia, argue that it is illogical to celebrate 31 August 1957 as Malaysia's national day when Malaysia was only established in 1963, before that there was no Malaysia. Supporters of Hari Merdeka argue that "the Federation" as defined in Article 160 of the Constitution of Malaysia is the "Federation of Malaya" that was established in 1957.