As prime minister, Sihanouk revoked a decree issued by the last resident superior of Cambodia, Georges Gautier, to romanise the Khmer alphabet. Following the Surrender of Japan in August 1945, nationalist forces loyal to Son Ngoc Thanh launched a coup, which led to Thanh becoming prime minister. When the French returned to Cambodia in October 1945, Thanh was dismissed and replaced by Sihanouk's uncle Sisowath Monireth. Monireth negotiated for greater autonomy in managing Cambodia's internal affairs. A modus vivendi signed in January 1946 granted Cambodia autonomy within the French Union. A joint French-Cambodian commission was set up after that to draft Cambodia's constitution, and in April 1946 Sihanouk introduced clauses which provided for an elected parliament on the basis of universal male suffrage as well as press freedom. The first constitution was signed into effect by Sihanouk in May 1947. Around this time, Sihanouk made two trips to Saumur, France, where he attended military training at the Armoured Cavalry Branch Training School in 1946, and again in 1948. He was made a reserve captain in the French army.