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 a treaty concerning the coordination of their economic policies in 1939, but the King could not persuade Adolf Hitler to guarantee Romania's frontiers. Romania was forced to cede Bessarabia and Northern Bukovina to the Soviet Union on 26 June 1940, Northern Transylvania to Hungary on 30 August, and Southern Dobruja to Bulgaria in September. After the territorial losses, the King was forced to abdicate in favour of his minor son, Michael I, on 6 September, and Romania was transformed into a national-legionary state under the leadership of General Ion Antonescu. Antonescu signed the Tripartite Pact of Germany, Italy and Japan on 23 November. The Iron Guard staged a coup against Antonescu, but he crushed the riot with German support and introduced a military dictatorship in early 1941.