The war in the latter half of 1915, marked by successes of Central Powers. German and Austrian advance in the East, Russian withdrawal. Italy enters the war on the Allied side, attacking Austria, and is stopped at the river Isonzo. The Allied offensive in Champagne and Artois falters. Serbia is overrun by German and Austrian troops with Bulgaria joining the war in this operation on the side of the Central Powers. Allied relief troops land in Salonika but are delayed by Greek internal politics, while Serb and Montenegrin forces and civilians flee through Albania to Corfu.