Axis Powers, coalition of countries that opposed the Allied powers in World War II. The coalition originated as the Rome-Berlin axis of National Socialist Germany and Fascist Italy, with the 1936 accord between Adolf Hitler and Benito Mussolini, and their military alliance of May 1939. Extended to include Japan in September 1940—the so-called Berlin Pact—it had as later adherents Bulgaria, Croatia, Hungary, Romania, and Slovakia. In addition, Denmark, Finland, Spain, and the pro-Japanese governments of Manchukuo and Nanking in China entered the coalition as adherents of the Anti-Comintern Pact signed by Germany and Japan in 1936. By the end of 1944 the Axis had been reduced to Germany and Japan (with the puppet Japanese governments in Manchukuo and Nanking) and four states being overrun by the Allies, that is, Hungary, Croatia, Slovakia, and Italy. The Axis came to a formal end when the Allies ratified the unconditional surrender of Germany on May 8, 1945.