The British High Commissioner's role became that of an ambassador following Singapore's independence from Britain and merger with Malaysia in 1963. Apart from that the executive branch of the Singapore Government remained largely unchanged, although now it governed a state within a larger federation. However, with effect from 9 August 1965, Singapore left the Federation of Malaysia and became a fully independent republic. On separation from Malaysia, the Singapore Government retained its executive authority, and the executive authority of the Parliament of Malaysia ceased to extend to Singapore and vested in the Singapore Government. The Yang di-Pertuan Agong, the Supreme Head of State of Malaysia, also ceased to be the Supreme Head of Singapore and relinquished his sovereignty, jurisdiction, power and authority, executive or otherwise in respect of Singapore, which revested in the Yang di-Pertuan Negara of Singapore. The Republic of Singapore Independence Act 1965 then vested the executive authority of Singapore in the newly created post of President, and made it exercisable by him or by the Cabinet or by any Minister authorized by the Cabinet.