The independence of Czechoslovakia was proclaimed on October 28, 1918, by the Czechoslovak National Council in Prague. Several ethnic groups and territories with different historical, political, and economic traditions had to be blended into a new state structure. In the face of such obstacles, the creation of Czechoslovak democracy was indeed a triumph.
Initial authority within Czechoslovakia was assumed by the newly created National Assembly on November 14, 1918. Because territorial demarcations were uncertain and elections impossible, the provisional National Assembly was constituted on the basis of the 1911 elections to the Austrian parliament with the addition of fifty-four representatives from Slovakia. National minorities were not represented; Sudeten Germans declared themselves part of Austria in the spirit of President Wilson's principle of self determination, and Hungarians remained loyal to Hungary. The National Assembly elected Tomáš Garrigue Masaryk as its first president, chose a provisional government headed by Karel Kramář, and drafted a provisional constitution.
The Paris Peace Conference convened in January 1919. The Czech delegation was led by Kramář and Beneš, premier and foreign minister respectively, of the Czechoslovak provisional government. The conference approved the establishment of the Czechoslovak Republic, to encompass the historic Bohemian Kingdom (including Bohemia, Moravia, and Silesia), Slovakia, and Carpathian Ruthenia. The inclusion of Ruthenia provided a common frontier with Romania, an important ally against Hungary. Těšínské Slezsko, an industrial area also claimed by Poland, was divided between Czechoslovakia (creating Zaolzie and leaving sizeable Polish minority on the Czech side of the border). The Czech claim to Lusatia, which had been part of the Bohemian Kingdom until the Thirty Years' War, was rejected. On September 10, 1919, Czechoslovakia signed a "minorities" treaty, placing its ethnic minorities under the protection of the League of Nations.
Tomáš Garrigue Masaryk was elected the country's first president in the 1920 election and his guidance helped to hold the country together. A coalition of five Czechoslovak parties, which became known as the "Petka" (The Five), constituted the backbone of the government and maintained stability. Prime Minister Antonin Svehla led the Petka for most of the 1920s and designed a pattern of coalition politics that survived until 1938. Masaryk was re-elected in 1925 and 1929, serving as President until December 14, 1935 when he resigned due to poor health. He was succeeded by Edvard Beneš.
Beneš had served as Czechoslovak foreign minister from 1918 to 1935, and created the system of alliances that determined the republic's international stance until 1938. A democratic statesman of Western orientation, Beneš relied heavily on the League of Nations as guarantor of the post war status quo and the security of newly formed states. He negotiated the Little Entente (an alliance with Yugoslavia and Romania) in 1921 to counter Hungarian revanchism and Habsburg restoration.
The leaders of Czechoslovakia needed to find solutions for the multiplicity of cultures living within one country. From 1928 and 1940, Czechoslovakia was divided into the four "lands" (Czech: "země", Slovak: "krajiny"); Bohemia, Moravia-Silesia, Slovakia and Carpathian Ruthenia. Although in 1927 assemblies were provided for Bohemia, Slovakia, and Ruthenia, their jurisdiction was limited to adjusting laws and regulations of the central government to local needs. National minorities were assured special protection; in districts where they constituted 20% of the population, members of minority groups were granted full freedom to use their language in everyday life, in schools, and in matters dealing with authorities. German parties also participated in the government in the beginning of 1926. Hungarian parties, influenced by irredentist propaganda from Hungary, never joined the Czechoslovak government but were not openly hostile.
When Adolf Hitler came to power in 1933, fear of German aggression became widespread in eastern Central Europe. Beneš ignored the possibility of a stronger Central European alliance system, remaining faithful to his Western policy. He did, however, seek the participation of the Soviet Union in an alliance to include France. (Beneš's earlier attitude towards the Soviet regime had been one of caution.) In 1935 the Soviet Union signed treaties with France and Czechoslovakia. In essence, the treaties provided that the Soviet Union would come to Czechoslovakia's aid only if French assistance came first.
The German minority living in Sudetenland demanded autonomy from the Czech government, claiming they were oppressed by the Czech government. In the 1935 Parliamentary elections, the newly founded Sudeten German Party under leadership of Konrad Henlein, financed with Nazi money, won an upset victory, securing over 2/3 of the Sudeten German vote, which worsened the diplomatic relations between the Germans and the Czechs. Henlein met with Hitler in Berlin on March 28 1938, where he was instructed to raise demands unacceptable to the Czechoslovak government led by president Edvard Beneš. On April 24, the SdP issued the Carlsbad Decrees, demanding autonomy for the Sudetenland and the freedom to profess Nazi ideology. If Henlein's demands were granted, the Sudetenland would then be able to align itself with Nazi Germany.