1917. After the October Revolution turned Russia from an ally into an enemy, Romania was forced to sign a harsh peace treaty with the Central Powers in May 1918, but the collapse of Russia also enabled the union of Bessarabia with Romania. King Ferdinand again mobilised the Romanian army on behalf of the Entente Powers a day before Germany capitulated on 11 November 1918. Austria-Hungary quickly disintegrated after the war. The General Congress of Bukovina proclaimed the union of the province with Romania on 28 November 1918, and the Grand National Assembly proclaimed the union of Transylvania, Banat, Crișana and Maramureș with the kingdom on 1 December. Peace treaties with Austria, Bulgaria and Hungary delineated the new borders in 1919 and 1920, but the Soviet Union did not acknowledge the loss of Bessarabia. Romania achieved its greatest territorial extent, expanding from the pre-war . A new electoral system granted voting rights to all adult male citizens, and a series of radical agrarian reforms transformed the country into a "nation of small landowners" between 1918 and 1921. Gender equality as a principle was enacted, but women could not vote or be candidates. Calypso Botez established the National Council of Romanian Women to promote feminist ideas. Romania was a multiethnic country, with ethnic minorities making up about 30% of the population, but the new constitution declared it a unitary national state in 1923. Although minorities could establish their own schools, Romanian language, history and geography could only be taught in Romanian. Agriculture remained the principal sector of economy, but several branches of industry—especially the production of coal, oil, metals, synthetic rubber, explosives and cosmetics—developed during the interwar period. With oil production of 5.8 million tons in 1930, Romania ranked sixth in the world. Two parties, the National Liberal Party and the National Peasants' Party, dominated political life, but the Great Depression in Romania brought about significant changes in the 1930s. The democratic parties were squeezed between conflicts with the fascist and anti-Semitic Iron Guard and the authoritarian tendencies of King Carol II. The King promulgated a new constitution and dissolved the political parties in 1938, replacing the parliamentary system with a royal dictatorship. The 1938 Munich Agreement convinced King Carol II that France and the United Kingdom could not defend Romanian interests. German preparations for a new war required the regular supply of Romanian oil and agricultural products. The two countries concluded