Battle of Transylvania
The Battle of Transylvania was the first major operation of Romania during World War I, beginning on 27 August 1916. It started as an attempt by the Romanian Army to seize Transylvania, and potentially knock Austria-Hungary out of the war. Although initially successful, the offensive was brought to a halt after Bulgaria's attack on Dobruja. Coupled with a successful German and Austro-Hungarian counterattack which started in mid-September, the Romanian Army was eventually forced to retreat back to the Carpathians by mid-October. The Romanian armies however managed to escape the Central Powers' attempts to completely destroy them. The Battle of Transylvania also caused the replacement of the Chief of Staff of the German Army and the shifting of German attention to the region, causing German offensive operations at Verdun to cease.
Background[edit]
Although bound by the pre-war Triple Alliance to the Central Powers, Romania instead joined the Triple Entente in August 1916, following the signing of the Treaty of Bucharest.
Officers from the Romanian General Staff began the planning of a potential invasion of Hungary as early as 1913, following Romania's successful expansion at Bulgaria's expense during the Second Balkan War. A draft document appeared in the summer of 1914, but Bulgaria's entry into the war on the side of the Central Powers in 1915 forced a major revision of the initial campaign plan. The final version, known as Hypothesis Z, was conceived by General Vasile Zottu. Hypothesis Z called for the Romanian occupation of Transylvania and Banat, using three armies (1st, 2nd and Northern) which amounted to a total of 420,000 soldiers (75% of Romania's field force). The 3rd Army, numbering 72,000 soldiers, was tasked with holding off a potential Bulgarian attack. Hypothesis Z envisioned an Austro-Hungarian opposing force numbering 70,000, but in reality, the actual number was less than half of the Romanian estimate. Another inaccurate Romanian estimate was the number of reinforcements that the Central Powers could deploy to the region: 100,000 compared to the actual number of 300,000.[5]
In July 1916, the Austro-Hungarians began preparations for an eventual defense of Transylvania. By early August, enough units had been gathered in order to form an army, the 1st. On 7 August, this new army was put under the command of General Arthur Arz von Straussenburg. Arz's army had four weak divisions (30-35 battalions) and around 100 artillery pieces in 13 batteries.[6] After the Romanian invasion commenced, the Austro-Hungarian 1st Army was reinforced with one cavalry division, one Reserve Hussar Brigade, one Honvéd infantry division and four battalions.[7]
Romanian invasion of Austria-Hungary, August 1916
Central Powers counterattack, September–October 1916
Operations on the front of the Romanian 1st Army during the ending phase of the Battle of Transylvania (6 - 14 October)
Operations on the front of the Romanian 2nd Army during the ending phase of the Battle of Transylvania (6 - 14 October)
Operations on the front of the Romanian North Army during the ending phase of the Battle of Transylvania (6 - 14 October) Note that the Romanians still held the town of Kézdivásárhely as late as 14 October; the town is shown at the extreme south of the map, surrounded by Romanian positions (thick red lines)
Battle of Sibiu
Battle of Brasov (Also note the operations at Kézdivásárhely in the northeast of the map: two Romanian units retreating from the north and northwest and forming a defensive perimeter around the town on 8–9 October)
