Royaume du Laos
Laos' first head of government was Phetsarath Ratanavongsa, who was appointed Prime Minister of the Kingdom of Luang Phrabang on 15 August 1941. A French–Lao agreement established the Kingdom of Laosthe first unified, modern Laotian stateon 27 August 1946. A Constituent Assembly was formed to enact a new constitution. The Constitution of the Kingdom of Laos was enacted on 28 April 1947 by the Constituent Assembly, and was promulgated by royal decree on 11 May 1947. Under the new constitution, Laos was defined as "a unitary, indivisible and democratic kingdom"; Prince Souvannarat was the first Prime Minister of the Kingdom of Laos. Seven prime ministers served the Kingdom of Laos between 15 March 1947 and its 2 December 1975 dissolution.