On 15 September 1918 French and Serbian mountain troops successfully attacked hitherto impregnable Bulgarian positions at Dobro Pole. Greek and British forces joined in, the Bulgarians, deprived of German and Austrian support, quickly found themselves in full flight, pursued by the Army of the Orient. The Bulgarian Tsar and government decided to seek an armistice, capitulating on 30 September, the first of the Central Powers to do so. According to its terms, Bulgarian troops had to evacuate all occupied Greek and Serbian territories, including Macedonia.