The harsh terms of the Treaty of Neuilly-sur-Seine (November 1919) limited the postwar Bulgarian army to 20,000, and conscription was forbidden. Many embittered former officers became politically active in the Military League, a formidable and wellorganized opposition faction in the 1920s and 1930s.

Irredentism made Bulgaria a natural ally of Germany during the interwar years. After border skirmishes with Bulgaria in 1925 and 1931, Greece joined Romania, Yugoslavia, and Turkey in forming the Balkan Entente in 1934 to contain perceived Bulgarian expansionism. Bulgaria began to rearm in 1936 with German, British, and French assistance. Meanwhile, the Military League had been influential in staging coups in the early 1930s. In 1936, however, Tsar Boris III (1918-43) dismantled the organization, stripping the military of the political influence it had accumulated after World War I.

After several years of hesitating between alignment with Germany or the Soviet Union, Bulgaria finally sought to satisfy territorial claims to the south and west by signing the Tripartite Pact with the Axis powers in March 1941. But Bulgaria minimized its involvement in the war, managing to satisfy the terms of alliance with Germany without a declaration of war on the Soviet Union.

In spite of its passive policy, Bulgaria was a vital pivot for German operations in the Balkans, North Africa, and on the eastern front against the Soviet Union. Germany launched invasions of Greece and Yugoslavia from Bulgaria in April 1941, and Bulgaria occupied parts of the territory it expected to retain after the war. German forces used the country as a rear area for transporting troops and supplies and providing training, and as a rest and recreation point. Its railroads and ports were critical to the German war effort. More than fifty German ships and submarines were berthed in the harbor at Varna as late as the summer of 1944.

The Bulgarian Communist Party (BCP) dominated the anti-German partisan movement that arose in 1941. Although the movement had a central military commission to direct armed activities, the partisans generally were poorly organized and armed. Their total number never exceeded 18,000 and, unlike partisans elsewhere, they were more active in the cities than in the countryside. The partisans received arms and supplies from the Soviet Union and Britain. The most successful aspect of partisan activity was proSoviet propaganda, demonstrations, terrorism, and sabotage against installations in Bulgaria critical to the German war effort. Among assassination attempts against German officials and Bulgarian fascists, the assassination of Minister of War Khristo Lukov in 1943 had the greatest impact. Harsh recriminations discouraged such activities, however. In 1943 the partisans formed the first fighting units of the People's Revolutionary Army of Liberation (PRAL), which eventually included brigade-sized units. Still, their armed attacks on German forces generally ended in failure. As late as 1944, entire units were captured or killed in action.

The Soviet Union declar367 ared war on Bulgaria on September 5, 1944, as the Red Army forces of the Third Ukrainian Front under General Fedor Tolbukhin crossed its northern border from Romania. Bulgaria changed sides on September 8 and declared war on Germany. Tolbukhin took command of the Bulgarian forces and reorganized them. By September 17, a Bulgarian army of 200,000 troops was mobilized and attached to the Third Ukrainian Front fighting German forces in Macedonia and Serbia. At the end of World War II, Bulgaria again returned the Greek and Yugoslav territory that it had occupied in 1941.

Data as of June 1992