Although Bulgaria, in alliance with Germany, Austria-Hungary and the Ottomans, won military victories against Serbia and Romania, occupying much of Macedonia (taking Skopje in October), advancing into Greek Macedonia, and taking Dobruja from the Romanians in September 1916, the war soon became unpopular with the majority of Bulgarian people, who suffered great economic hardship and also disliked fighting their fellow Orthodox Christians in alliance with the Muslim Ottomans. The Agrarian Party leader, Aleksandar Stamboliyski, was imprisoned for his opposition to the war. The Russian Revolution of February 1917 had a great effect in Bulgaria, spreading antiwar and anti-monarchist sentiment among the troops and in the cities. Membership in socialist parties in Bulgaria boomed. However, the socialists in Bulgaria were badly split ideologically. One group sought to work with other political parties representing other classes in order to be effective in bringing change to Bulgaria. Because of their "broad outlook" this group of socialists was known as the "broads." The second group of socialists in Bulgaria were purists and refused to work with parties of different classes. They were called the "narrows." Eventually, the broads formed themselves into the Bulgarian Social Democratic Party and the narrows became the Bulgarian Communist Party.