The Russian offensive of 1916 was intended to complement the anticipated attack by French and British forces on the western front. Just as the German offensive at Verdun disrupted the Allies' intentions in the West, so also did it reshape the Russian role in 19r6. In part to help take pressure off Verdun, the Russians advanced sooner than planned; they also struck a lesser blow than originally intended. Instead of a large-scale offensive over much of the eastern front, the Russian attack involved only a single army group (under General Alexis Brusilov) striking Austro-Hungarian forces in the southern half of the theater of operations. In short order, German reinforcements rushed to the scene (possibly taking some of the pressure off Verdun), and Brusilov's promising attack trailed off into a new stalemate. The shock of the Brusilov offensive had a notable effect on the relations between Austria-Hungary and Germany on the eastern front. The two countries now placed their forces there under a unified German-led command. Bloody offensives took place on the two fronts on which Italy's army faced its Austrian opponents. Under Cadoma, the Italian forces continued their futile and costly offensives on the Isonzo. In a novel twist to the fighting on the Italian front, the Austrians took the offensive in the northern (Trentino) sector in May. In both sectors, as always, the defending side had the better of the fight. Operations on one front took place in the shadow of events elsewhere: Brusilov had moved up the time of the Russian army's offensive in part to aid the Italians struggling to hold on to the Trentino. As in 1915, spectacular advances and decisive victories took place away from the quagmire of the western front. On August 27, 1916, encouraged by the initial success garnered by General Brusilov, the government of Rumania abandoned its neutrality and joined the Entente. The Rumanians made the mistake of immediately advancing westward into Transylvania, a part of the Austro-Hungarian Empire inhabited largely by ethnic Rumanians. This promising move brought no results worth the effort. The poorly trained and badly led Rumanian army advanced in halting fashion over difficult mountain roads, hindered by an increasingly effective Austrian defense. And no sooner had they begun their assault than they found their own country being attacked. German generals showed once again what they could do against an inferior enemy in the wide spaces of the eastern front. Within a week after the start of hostilities, General August von Mackensen, Germany's leading combat commander in the east, drove northward into Rumania from bases in Bulgaria. General von Falkenhayn had been relieved as chief of staff for his failure at Verdun, but he received command of the field army that counterattacked eastward from Transylvania in mid-September. By year's end, most of Rumania, like northeastern France, Belgium, Serbia, and Russian Poland, came under German occupation. In the north, the Rumanian army, like the Belgian, was able to hold only a small sliver of the kingdom's territory.