Romania entered the war on the Allied side after gaining prior acceptance of their territorial claims to Transylvania through the Treaty of Bucharest. With the Central Powers under extreme pressure on both fronts through the Somme and Brusilov offensives, Romania launched their Romanian Campaign on 27 August 1916 and within days had occupied much of Transylvania. Germany was quick to respond, mounting a counteroffensive through the territory of its Bulgarian ally. With the aid of Ottoman reinforcements, it captured a string of towns in southern Romania including the stronghold of Tutracaia. The Central Powers forces were now arrayed along the southern banks of the Danube and threatening the vital rail link between Romania’s capital Bucharest and Constanta on the Black Sea. In the middle of September, Romania’s war council suspended the advance in Transylvania and, with belated Russian reinforcements, concentrated on repelling the southern invasion.
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