already occupied by Jews and Germans. This contributed to the national tensions among the Poles, Germans, and Jews. At this time the Jewish population in Prussian Poland tended to identify with and want to belong to Germany, insofar as the latter, like the Jews themselves, had a more urbanized, cosmopolitan outlook. Another factor, not to be overlooked or underestimated is the traditional language spoken by the Ashkenazi Jews of Central and Eastern Europe, Yiddish, is also a Germanic language written in Hebrew characters, which afforded some natural compatibility with the German language dominated Austria-Hungarian and Prussian cultures. These transformations changed the face of politics as well, giving rise to new parties and movements that would dominate the Polish landscape for the next century. The grievances of the lower classes led to the formation of peasant and socialist parties. Communism gained only a marginal following, but a more moderate socialist faction led by Józef Piłsudski won broader support through its emphatic advocacy of Polish independence. By 1905 Piłsudski's party, the Polish Socialist Party, was the largest socialist party in the entire Russian Empire. The National Democracy of Roman Dmowski became the leading vehicle of the right by espousing a doctrine that combined nationalism with hostility toward Jews and other minorities. By the turn of the 20th century, Polish political life had emerged from the relative quiescence of Organic Work and entered a stage of renewed assertiveness. In particular, Piłsudski and Dmowski had initiated what would be long careers as the paramount figures in the civic affairs of Poland. After 1900 political activity was suppressed only in the Prussian sector. First World War At the outbreak of the First World War Poland's geographical position between Germany and Russia had meant much fighting and horrific human and material losses for the Poles between 1914 and 1918. At the Treaty of Brest-Litovsk in spring 1918, revolutionary Russia renounced Russian claims to Poland. Following the German defeat and the replacement of Hohenzollern rule by the Weimar Republic and the collapse of Habsburg Austria-Hungary, Poland became an independent republic. War and the Polish lands The war split the ranks of the three partitioning empires, pitting Russia as defender of Serbia and ally of Britain and France against the leading members of the Central Powers, Germany and Austria-Hungary. This circumstance afforded the Poles political leverage as both sides offered pledges of concessions and future autonomy in exchange