The Royal Lao Government was the ruling authority in the Kingdom of Laos from 1947 until the communist seizure of power in December 1975 and the proclamation of the Lao People's Democratic Republic. The Franco-Lao Treaty of 1953 gave Laos full independence but the following years were marked by a rivalry between the neutralists under Prince Souvanna Phouma, the right wing under Prince Boun Oum of Champassak, and the left-wing, Lao Patriotic Front under Prince Souphanouvong and future Prime Minister Kaysone Phomvihane. During this period, a number of unsuccessful attempts were made to establish coalition governments.