When in 1923 the Allies recognized Polish rule over western Ukraine, the underground Ukrainian Military Organization (Ukrainska viiskova orhanizatsiia, UVO), composed of Ukrainian veterans, turned to Germany and Lithuania for political and financial support. It established contact with militant anti-Polish student organizations, such as the Group of Ukrainian National Youth, the League of Ukrainian Nationalists, as well as the Union of Ukrainian Nationalist Youth. After preliminary meetings in Berlin in 1927 and Prague in 1928, at the founding congress in Vienna in 1929 the veterans of the UVO and the student militants met and united to form the OUN. Yevhen Konovalets served as its first leader, while its leadership council, the Provid, was comprised mostly of veterans based abroad. (?) After the assassination of Konovalets in 1938, Andriy Melnik was elected leader of the group. Melnik belonged to the older generation of OUN sympathisers, and was challenged by his younger competitor Stepan Bandera (1909-1959), who wanted to militarise the OUN.