Bulgarian – Serbian Wars ( medieval ) The Bulgarian - Serbian wars were a series of conflicts between the Bulgarian Empire and the medieval Serbian states of Raška , Duklja , and the Kingdom of Serbia between the 9th and 14th centuries in western Serbia , Bosnia , and Kosovo in the western Balkans . Before the 12th century , the Serbian states were dependent upon and strongly influenced by the dominant Balkan powers , the Bulgarian and Byzantine Empire s . The rulers of both those countries sought to control Serb princes to use them as allies in the Byzantine - Bulgarian Wars . The first war between Bulgarians and Serbs occurred during the reign of Khan Presian between 839 and 842 , precipitated by Byzantine diplomacy . Later after series of campaigns the Bulgarian Emperor Simeon I destroyed the Serb state in 924 . The Bulgarian Emperor Peter I granted formal independence to Serbia in 931 and appointed his protégé Časlav Klonimirović as its ruler . They were again subjected by Emperor Samuil in 998 . In the 13th century Stefan Dragutin and his brother Stefan Milutin fought as Hungarian vassals against the Bulgarian governors of Belgrade and Braničevo , Darman and Kudelin and managed to defeat them . In 1327 the Emperors of Bulgaria and Byzantium signed an anti - Serbian alliance to stop Serbia ' s growing power but in 1330 Bulgarian Emperor Michael III Shishman was defeated by Stefan Dečanski in the battle of Velbazhd . Wars of the 9th century . According to Byzantine sources , the Bulgarians and the Serbs co - existed peacefully prior to the 9th century . In 818 Slavic tribes along the Timok River rebelled against the increasingly centralized Bulgarian suzerainty along its western frontier . Khan Omurtag launched an attack into the disputed lands in 827 , secured control over territory as far as Pannonia , expelled the local Slavic chiefs , and installed Bulgarian governors . Serbian tribes began to unify under a prince named Vlastimir in resistance to Bulgarian expansion , and the Byzantine emperor Theophilos , who was officially overlord of the Serbian tribes , supported this unity and probably granted the Serbs independence as a counterweight to the Bulgarians . According to Porphyrogenitus , the Bulgars sought to continue their conquest of Slav lands and to force the Serbs into subjugation . Bulgarian khan Presian I ( r . 836 – 852 ) launched an invasion into Serbian territory in 839 , leading to three years of war . Presian was heavily defeated , lost a large part of his army , and made no territorial gains . The Byzantines achieved their objective , however , as Bulgarian attentions were diverted , and the Byzantines managed to cope with Slavic rebellions in Pelopones . The war ended with the death of Theophilos in 842 , releasing Vlastimir from his obligations to the emperor and giving the Bulgarians the opportunity to attack the Byzantine Empire and annex the area of Ohrid , Bitola , and Devol in 842 – 843 . Vlastimir died in about 850 , and his state was divided between his sons Mutimir , Strojimir , and Gojnik . In 853 or 854 , the new Bulgarian ruler Boris I sent an army , led by his son Vladimir , to attack the Serbs , aiming to replace Byzantine influence over them . The Serbian army led by Mutimir and his brothers defeated the Bulgarians , capturing Vladimir and twelve leading boyars , who had to be ransomed . Boris I and Mutimir agreed on peace ( and perhaps an alliance ) . Mutimir sent his sons Pribislav and Stefan to escort the prisoners to the border , where they exchanged items as a sign of peace . Boris himself gave them " rich gifts " , receiving in return " two slaves , two falcons , two dogs , and 80 furs " . Mutimir soon seized the Serbian throne , exiling his brothers to the Bulgarian court , and ruled until his death in about 890 . A power struggle ensued within the ruling family before Mutimir ' s nephew Peter emerged to capture the throne in 892 , gaining the recognition of the Bulgarian khan , Simeon . This resulted in twenty years of peace within Serbia and a Serbian - Bulgarian alliance from 897 - 917 . Campaigns of Simeon I . For the next half century following the campaign of Boris I , both countries were at peace , and the Serbs looked to Bulgaria as a source of their culture . In 917 the Byzantines managed to bribe the Serbian prince Petar Gojniković to turn against his ally , Simeon I . After the Byzantine army was annihilated in the battle of Achelous on 20 August that year , the Bulgarian emperor had to delay his march to Constantinople in order to secure his western borders . In the autumn of 917 Simeon sent an army under the generals Theodore Sigritsa and Marmais to invade Serbia and punish Gojniković for his treason . They convinced Petar Gojniković to meet them , but when the Serbian Prince came he was captured and taken to Preslav where he died in prison . The Bulgarians installed Petar ' s cousin Pavle Branović , who was under the wing of Simeon , in his place . In 921 , the Bulgarians controlled almost every Byzantine possession on the Balkans , and the latter tried once again to turn the Serbs against Bulgaria . Romanos Lekapenos sent Zaharije Pribisavljević against Pavle , who was loyal to Simeon , but Zaharije was defeated and sent to Bulgaria , to be used against Pavle if the latter was insubordinate . However , the Byzantines managed to bribe Pavle , and while the Bulgarians were besieging Adrianople , the Serbs started hostilities against Bulgaria . This time Simeon easily defeated them - he sent Zaharije with a Bulgarian army into Serbia . Pavle was defeated , and his throne was taken by Zaharije . Zlatarski dates that campaign to 922 , while Fine suggests it took place in the period between 921 and 923 . Byzantine historians , however , wrote that after Zaharije " recalled the beneficence of the Byzantine Emperor , [ he ] immediately rebelled against the Bulgarians because he did not want to submit to them but preferred to be a subject of the Byzantine Emperor . " Since Zaharije had long lived in Constantinople , it was not difficult for the Byzantines to win him as an ally . Angered with his betrayal , in 924 Simeon sent an army led by Theodore Sigritsa and Marmais to crush the Serbs , but the Bulgarians were insufficient in number . They were ambushed and defeated , and the heads of their commanders were sent to Constantinople . Enraged , Simeon pretended that he was ready to conclude peace with the Byzantine Empire and in the meantime summoned a large army against the Serbs under the generals Knin , Imnik and Itsvoklius along with the new pretender of the Serbian throne Časlav Klonimirović . When the news of those preparations reached Zaharije , he immediately fled to Croatia . However , this time the Bulgarians decided to fully conquer the Serbian principality . The Serbian nobles were persuaded to meet Časlav and were captured and taken to Preslav . The Bulgarian army devastated Serbia and moved the population to Bulgaria while some escaped to Croatia and Byzantium . Serbia was included in the borders of the Bulgarian Empire for a period of several years until 931 when prince Časlav managed to escape from Preslav and organized a successful revolt against the new emperor Peter I . Campaigns of Samuil . After the defeat at Spercheios in 996 against the Byzantines , the Bulgarian Emperor Samuil turned his attention to the Serbian and Croatian principalities to the northwest where the Byzantine influence was very strong . In 998 he invaded the Serbian principality of Duklja , which was ruled by Prince Jovan Vladimir . The Serbs were unable to resist the Bulgarian army , and Jovan Vladimir fled with his people in the Oblica mountain . When Samuil arrived he left part of his army to bar the Serbs , and with the rest of his troops he besieged the coastal fortress of Ulcinj . To avoid further bloodshed the Bulgarians offered to allow Jovan Vladimir to surrender ; he initially refused , but after it became clear that his nobles were ready to betray him , he surrendered to Samuil . Jovan Vladimir was exiled to Samuil ' s palaces in Prespa . Then the Bulgarians seized Kotor and set off for Dubrovnik and Dalmatia . While Jovan Vladimir was in Bulgarian captivity , one of the daughters of Samuil , Theodora Kosara , fell in love with the young Serbian Prince , and Samuil approved their marriage . Jovan Vladimir was allowed to return to his lands as a Bulgarian official , supervised by a trusted man of the Bulgarian Emperor , Dragomir . However , in 1016 he was killed by the new Bulgarian Emperor Ivan Vladislav who was suspicions that Vladimir could be a potential candidate for the throne . Conflicts in the 13th century . The first clashes between the reborn Bulgarian Empire and the Serbs who acted as Hungarian vassals appeared in 1202 . Emeric of Hungary took advantage of the campaigns of the Bulgarian Emperor Kaloyan and took the Bulgarian cities Belgrade , Branicevo and Niš . The latter was given to his vassal , the Serbian zhupan Valkan . However , on the next year the Bulgarian army pushed the Serbs out of Niš ( which Fine suggest that was under Serbian rule since the 1190s ) and defeated the Hungarians in the battles along the Morava river . In 1289 the Hungarians asked their vassal Stefan Dragutin to attack the Bulgarian nobles Darman and Kudelin , rulers of the Branicevo province , who had previously defeated the Hungarians . In 1290 Dragutin invaded the province but was defeated by Darman and Kudelin who on their turn attacked his lands . Dragutin had to ask his brother Stefan Milutin , the King of Serbia to help him . In the next year they defeated the Bulgarians who fled to Vidin . The despot of Vidin also fought against the Serbs but the war was unsuccessful and Vidin was sacked . Bulgaria lost the Belgrade and Branicevo provinces forever . War of 1330 . After 1291 both states maintained friendly relations . In 1296 the Bulgarian Emperor Smilets married his daughter Theodora to the future Serbian King Stefan Uroš III Dečanski . The sister of Dečanski Anna Neda was married to the Bulgarian Emperor Michael III Shishman . However , the growth of the Serbian Kingdom in the late 13th and early 14th century raised serious concern in the royal courts in Tarnovo and Constantinople - while both Empires had numerous external and internal problems , the Serbs expanded their state in northern Macedonia . On 13 May 1327 Michael III Shishman and Andronikos III Palaiologos signed a treaty against Serbia and agreed to launch joined campaign . The two emperors had some disputes but they were cleared by 1328 and the alliance was reaffirmed in October that year . The campaign began in July 1330 when the Byzantine invaded Serbia from the south but after they seized several fortresses their campaign was halted by orders of Andronikos III . In the meantime the Bulgarian army which numbered around 15 , 000 men attacked from the east . On 24 July the armies of Bulgaria and Serbia ( which numbered between 15 , 000 and 18 , 000 men ) met near the town of Velbazhd ( Kyustendil ) . Despite the one - day truce agreed by the two rulers , the Serbs broke their word and attacked the Bulgarians while the latter were scattered to search for provisions . Caught by surprise and outnumbered , the Bulgarians tried to organize resistance but were defeated and the wounded Emperor Michael III Shishman was captured by the victors and died four days later . Despite their victory , the Serbs were unable to continue their campaign in Bulgaria - Stefan Dečanski did not risk to confront the Bulgarian reserves led by the Emperor ' s brother and despot of Vidin Belaur and the despot of Lovech Ivan Alexander . Furthermore , he was under pressure from the south where there were Byzantine forces . After short negotiations near the castle of Izvor Belaur and Dečanski concluded a peace treaty according to which the Bulgarian throne was inherited by Michael III Shishman ' s and Anna Neda ' s son Ivan Stefan . Bulgaria did not lose territory but was unable to stop the Serbian expansion in Macedonia . Fine writes that although sourses mention no territorial changes , many scholars believe that the Serbs seized Nis and the surrounding region in the aftermath of the battle . Conclusion . The battle of Velbazhd opened a period of 20 years in which for the first time Serbia became the dominant power of the Balkans . Their new King Stefan Dušan in 1331 conquered Macedonia , Epiros and Thessaly and in 1346 was crowned Emperor with the help of the Bulgarians . After his death in 1355 his state was divided into several independent states as did Bulgaria during the rule of Ivan Alexander in 1371 . In the 15th century both states were destroyed by the Ottoman Turks .