Second Battle of Artois
On the battlefields far from Bulgaria, the war had entered a long period of stalemate with no side appearing to gain the upper hand. On the Western Front in February 1915, the French failed to break the German lines at the First Battle of Champagne, while further attempts at the Second Battle of Artois during May also came to an unsuccessful conclusion. The Germans had decided to focus their efforts on the Eastern Front, where they had considerable success against the Russians in the Second Battle of the Masurian Lakes in February 1915, but their gains were largely negated at the Siege of Przemyśl in March. The Germans and Austrians then undertook new counterattacks to restore their positions. Finally, in May 1915, Italy entered the war on the side of the Entente. Under these circumstances, the military and political value of the neutral Balkan countries increased significantly.