Leading lesser allies is a classic feature of coalition warfare. That was Britain’s task in the Entente. Through diplomacy and blackmail, London tried to reconcile Rome’s national interests with the needs of the Entente.

Many of the war’s leading generals rose or fell during 1916. Germany refocused on the west, where Falkenhayn, chief of the high command since the initial defeat at the Marne, attacked at Verdun, seeking a bloodletting that would drive France from the war. The French persevered through ten months, during which generals Pétain and Nivelle eclipsed Joffre, who lost his post as commander late in the year. In the summer Haig’s British and Imperial forces, with French support, attacked the Germans at the Somme, where in September tanks first saw action. The battle there ended in a draw but also ensured the French a draw at Verdun. Meanwhile, on the Italian front, Conrad von Hötzendorf launched an Austro-Hungarian offensive from the Tyrol. This attack, like the German effort at Verdun, used troops pulled from the east, allowing a summer Russian offensive under Brusilov to break the weakened front. The Germans returned troops to seal the breach, but the debacle forced Falkenhayn to relinquish the high command to Hindenburg and Ludendorff. Amid the crisis the Central Powers made William II their supreme commander, sealing Austria-Hungary’s subordination to Germany. Bulgaria and the Ottoman Empire joined them late in the year in crushing Romania shortly after it joined the Allies.