Europe 1915: Central Power Breakthrough in the East

Italy joined the Allies in May, but the rest of the year favored the Central Powers. In August the Germans pushed the Russians out of Poland, while in October the Bulgarians joined the War and helped defeat Serbia. The Allies landed in officially neutral Greece in an attempt to save the Serbs, but were only able to rescue part of their fleeing army.

Main Events

1 May–18 Sep 1915 Gorlice-Tarnow Offensive

Germany overruns Poland and Lithuaniain wikipedia

7 May 1915 Sinking of the RMS Lusitania

German submarine U-20 torpedoed the RMS Lusitania in the North Atlantic Ocean off the southwest coast of Ireland, sinking her. The action killed 1,198 of the 1,959 people aboard, including 128 of 139 American passengers. Although she was a British ship carrying munitions and the German Embassy in Washington had issued a warning implying that she might be attacked, the sinking shocked the United States and helped galvanize opinion against Germany. In response, on 9 September 1915, Germany ordered the restriction of U-boat attacks to ships that were confirmed to be British, with no actions against passenger liners permitted at wikipedia

23 May 1915 Italian entry into WWI

Following the secret promises of territory made by the Allies in the Treaty of London, the Kingdom of Italy declared war on Austria-Hungary, entering World War I on the side of the Allies. This act occurred only 19 days after Italy’s denouncement of its membership in the Triple Alliance with Austria-Hungary and wikipedia

3 Oct 1915 Macedonian Front

Allies land at Salonika in Greecein wikipedia

8–9 Oct 1915 Austria-Hungary and Germany capture Belgrade

Austria-Hungary and Germany capture Belgradein wikipedia

14 Oct 1915 Bulgaria’s entry into WWI

The Kingdom of Bulgaria declared war on the Kingdom of Serbia, bringing Bulgaria into World War I on the side of the Central Powers. Its entry both doomed Serbia—by creating another front—and ensured the continuation of the Ottoman war effort by opening up the way for material assistance from wikipedia