Battle of Slivnitsa Called by historians the " Battle of the captains " vs " the generals , " referring to the young Bulgarian army , whose highest rank went up to a captain , the Battle of Slivnitsa ( , ) was a decisive factor in the victory of the Bulgarian army over the Serbians on November 17 – 19 , 1885 in the Serbo - Bulgarian War . It solidified the unification between the kingdom of Bulgaria and Eastern Rumelia . Background . The conclusion of the Russo - Turkish War ( 1877 - 1878 ) and the Congress of Berlin 1878 left Bulgaria divided into two sections . The area north of the Balkan Mountains and Sofia became an autonomous principality . Eastern Rumelia between the Balkan and Rhodope mountains gained semi - autonomous status with an Ottoman appointed Christian governor . The Bulgarian Assembly chose Prince Alexander Battenberg as their ruler and continued to press for the reunification of their country . Political changes in 1883 caused a cooling in relations between Bulgaria and their protector Russia , who now opposed reunification . In September 1885 a rebellion broke out in Eastern Rumelia . Alexander was placed in a difficult position . Russian opposition if he supported the revolt , or the loss of his throne unless he retained leadership of the Bulgarian national movement . He decided to keep his throne . In response the Russians recalled all their officers which left the Bulgarian army virtually leaderless above the rank of Captain . The Bulgarian army concentrated their limited forces in Eastern Rumelia , expecting an Ottoman attack that never materialised . The actual threat came from the west in the shape of King Milan ' s Serbia . Bulgarian unification upset the balance of power in the Balkans and Milan demanded compensation . The Armies . The Bulgarian field army in 1885 consisted of just under 30 , 000 men organised into 8 , three battalion infantry regiments ( 700 men each ) , 9 squadrons of cavalry and 12 , eight gun batteries . In addition the first line of the Eastern Rumelia militia had been mobilised consisting of 12 infantry battalions , 2 squadrons of cavalry and 4 guns . During the war the second ban of the Eastern Rumelia militia was mobilised ( 12 battalions ) along with the Bulgarian second ban ( 8 battalions ) and as many as 20 volunteer battalions , 3 Macedonian battalions and some 6000 Muslim volunteers . Confident of an easy victory and to some extent recognising that the war was not popular in Serbia , Milan only mobilised the active ( first ban ) army . This gave a field army of 5 divisions consisting of 80 battalions ( 700 men ) , 21 cavalry squadrons and 46 batteries . A total of 70 , 000 men and 264 guns . In fact only 49 battalions and 23 batteries were ready for the invasion , the rest along with elements of the second ban only became available in the last stage of the war . A key weakness was the limited number of modern Krupp and du Bange guns . The Opening Moves . Serbia declared war on 13 November 1885 and crossed the lightly defended north - western border in three columns . The main army in the centre ( Šumadija , Danube and Drina divisions ) . To the south the Morava division and to the north the Timok division . The plan was to break through the Bulgarian defences and concentrate four divisions before Sofia . In response Alexander had to move his army from Eastern Rumelia to Sofia by all means available including the one limited railway line . One infantry regiment marched 95 km in 32 hours . The light Bulgarian forces on the Serbian border succeeded in slowing the Serbian advance in mountainous terrain which favoured the defence . Gradually reinforcements arrived at the previously prepared defensive position at Slivnitsa , 30 km north - west of Sofia . Slivnitsa 17 / 19 November 1885 . Alexander arrived on the evening of the 16th to find a well prepared defensive position manned by 9 battalions , plus some 2000 volunteers and 32 guns , commanded by Major Guchev . The position consisted of nearly 4 km of trenches and artillery redoubts either side of the main road on a ridge in front of Slivnitsa village . To the right was steep mountainous terrain whilst the left wing had the easier Visker Hills towards Breznik . The three Serbian centre divisions also arrived on the 16th and halted to recover after the fierce Bulgarian delaying action in the Dragoman Pass . The Morava division was at Tran some distance from its objective Bresnik to the south . The northern advance was bogged down along the Danube . The morning of the 17th came with rain and mist but not the expected Serbian attack . By 10am Alexander ordered three battalions to advance on the right . They surprised the Danube division who eventually rallied and pushed them back . The main Serbian attack began on the centre largely unsupported by artillery which had insufficient range . The weight of Bulgarian fire forced them back with some 1200 casualties . A relief column led by Captain Benderev recaptured the heights on the right and forced the Danube division back to the road . At daybreak on the 18th the Serbians attacked the weaker left flank of the Bulgarian line . Just in time two battalions of the Preslav Regiment arrived to shore up the position . Further attacks in the centre were repulsed with heavy Serbian casualties and Benderev captured two further positions in the mountains . On the 19th the Serbians concentrated two divisions for an attack on the Bulgarian left near Karnul ( today Delyan , Sofia Province ) in an attempt to join up with the Morava division . However , three battalions of Bulgarian troops led by Captain Popov from Sofia had held the Morava division in the Visker Hills and the flanking move failed . Alexander now ordered a counter attack which pushed the Serbians back on both flanks although nightfall prevented a complete collapse . The Bulgarians Advance . Slivnitsa was the decisive battle of the war . The Serbians fought only limited rearguard actions as they retreated and by 24 November they were back in Serbia . The Timok division in the north continued the siege of Vidin until 29 November . The main Bulgarian army crossed the border in two strong divisions ( Guchev and Nikolaev ) supported by flanking columns and converged on Pirot . The Serbian army dug in on the heights west of the town . On 27 November the Bulgarian army flanked the right of the Serbian position with Prince Alexander personally leading the final attack . The Serbians were defeated and fled to Niš . On the 28th the Austrians intervened and a ceasefire was agreed . Serbian casualties totalled 6 , 800 compared to 2 , 300 Bulgarians . Serbian sources state that the casualties in this battle totaled 3 , 000 for the Serbs vs 2 , 500 for the Bulgarians , and . 7 , 000 for the Serbs vs 5 , 000 for the Bulgarians in the whole war . The Treaty of Bucharest 1886 effectively confirmed the unification of Bulgaria . A major achievement for an army shorn of its senior officers . Unfortunately for Prince Alexander Russia continued to oppose his reign and he was deposed by the Russophile officers in August 1886 . References . This article plus maps was also published in The Foreign Correspondent , the journal of the Continental Wars Society .