21 June when the First Army was ordered to advance against the town of Knjaževac and after it had occupied it to divide its forces in two with one part to be directed against Zaječar and the other one send to assist the Third army around Pirot. Facing the First Army was the Timok Army of 31 battalions and 12 gun batteries—mostly third line infantry, commanded by colonel Vukuman Arachich. The Bulgarians managed to defeat part of these forces and occupy Knjaževac while suffering only 280 men killed and 820 men wounded. Meanwhile, Romania had declared war on Bulgaria and its army had begun invading the northern part of the country. This new enemy threatened the rear of the First Army and forced the Bulgarian high command to order its retreat back to the border. That move had a very negative effect on the morale of the troops and even caused opened mutinies in the Ninth Division which became completely disorganized during the retreat. The situation was particularly bad in the division's Second Brigade which surrendered to the Romanian forces around Montana. The rest of the Ninth managed to retreat to Sofia and later form the Samokov detachment which took an important part in the Battle of Kresna Gorge. The rest of the army also retreated towards Sofia and took defensive positions in the Balkan mountain passes. The Serbians took advantage of this and occupied Belogradchik where they established contact with the Romanian Army. Even though by now most of northwestern Bulgaria was lost, General Kutinchev kept a few battalions in the fortress of Vidin which managed to hold off all Serbian attacks until the end of the war. The Bulgarian high command now planned a decisive offensive operation against the Greek Army which was advancing in the Kresna Gorge. For that purpose Lieutenant General Vasil Kutinchev was assigned commander of the Second Army and the units of the First Army were transferred south to reinforce it. A general armistice was concluded on 18 July 1913 and ten days later the Treaty of Bucharest, which stipulated immediate demobilization of the Bulgarian Army, was signed. First World War Conquest of Serbia With the outbreak of the Great War Bulgaria declared neutrality, as it still hadn't recovered from the losses suffered in the Balkan Wars. In 1915 activities in the diplomatic arena intensified and both the Entente and the Central powers tried