Klonimir Klonimir ( , ; fl . 896 ) was a Serbian prince of the Vlastimirović dynasty , and pretender to the throne of the Serbian Principality . His father and uncle , co - princes Strojimir and Gojnik , had been exiled to Bulgaria with their families after their eldest brother Mutimir had ousted them and taken the Serbian throne . Klonimir married a Bulgarian noblewoman chosen by Khan Boris I himself . She later gave birth to a son named Časlav . The descendants of the three Vlastimirović branches continued the feud over the Serbian throne which spanned over the century , and Klonimir returned to Serbia in ca . 896 and attempted to take the country from his cousin Petar , who had ruled since 891 . He managed to take over the Serbian city of Destinikon , but the much more powerful Petar defeated him , and it is presumed that Klonimir died in battle . His son Časlav later became the most powerful of the Vlastimirović dynasty , as Prince of Serbia from 927 to 960 , unifying several tribes in the region . Life . The history of the early medieval Serbian Principality and the Vlastimirović dynasty ( ruled ca . 610 – 960 ) is recorded in the work " De Administrando Imperio " ( On the Governance of the Empire ) , compiled by the Byzantine Emperor Constantine VII Porphyrogenitus ( r . 913 – 959 ) . Vlastimir , the eponymous founder of the Vlastimirović dynasty and the ruling Serbian Prince ( " archon " ) in the period of ca . 830 – 851 , was a Byzantine ally who had managed to devastate the Bulgarians in a three - year war ( 839 – 842 ) , and greatly expand the Serbian realm to the west . Upon his death , the rule was inherited by his three sons , Mutimir , Strojimir and Gojnik , though supreme rule was held by the eldest , Mutimir . The three brothers successfully fought off a Bulgarian attack in 853 or 854 ( shortly after the death of Vlastimir ) , when they had managed to capture 12 great boyars and the commander himself , Vladimir , the son of Khan Boris I of Bulgaria ( r . 852 – 889 ) . The Bulgars sought to avenge the defeat of their previous Khan , Presian . The Serbs and Bulgars then made peace , and possibly formed an alliance . A quarrel eventually broke out between Vlastimir ' s three sons . Mutimir , the eldest , sought supreme leader ship of the Serbian throne ; as the co - ruling younger brothers , Strojimir and Gojnik , resisted , he had them captured and exiled to Bulgaria , where they were most likely held as hostages at the Bulgarian court at Pliska , after 855 / 856 . According to V . Ćorović , Boris wanted to gain influence on these events in Serbia and sought to help those who could stand on the Bulgarian side instead of the Byzantine , and thus he graciously received the two younger brothers , holding them as weapons for his needs . Evidence of this is the fact that Boris himself chose a Bulgarian noblewoman to marry Strojimir ' s son , Klonimir . It seems that the exiled families were treated well in Bulgaria , with respect to their status . Mutimir had not exiled all members of his brother ' s families , but had retained his nephew Petar , the son of Gojnik , at the Serbian court for political reasons , although Petar later feared his father ' s fate and eventually escaped across the western border to Croatia . The descendants of Vlastimir ' s sons continued to fight for the throne over the century . An important event was the Christianization of the Serbs which began in 870 , accompanied by strong political and cultural influences from the Byzantine Empire . After Mutimir ' s death in 890 or 891 , the rule of Serbia was inherited by Mutimir ' s three sons Pribislav , Bran and Stefan ( called the " Mutimirović " ) , headed by the eldest son , Pribislav . However , Pribislav ' s reign only lasted less than a year , ending when his cousin Petar returned to Serbia from Croatia and won a battle against Pribislav . Petar acquired the Serbian throne in ca . 892 . Mutimir ' s three sons then left Serbia for Croatia where they sought refuge and help . In ca . 894 , Bran tried to oust Petar with Croatian help but was unsuccessful ; he was captured and blinded ( according to political mutilation culture ) . In ca . 896 , Klonimir left Bulgaria and marched an army into Serbia , entering the Serbian city of Destinikon ( , also spelled " Destinika " and ) , with the intent of seizing the throne . This city ' s exact location is undetermined , as " De Administrando Imperio " only lists it as one of eight fortified cities ( καστρα ) of Serbia proper ( not counting those of the maritime Serbian principalities ) . P . Skok , Relja Novaković and Vojislav Korać believed it to be Drsnik , in Metohija . Stojan Novaković and K . Grot believed it to be Deževa , in Raška . P . J . Šafárik believed it to be on the Lower Drina , near the villages of Disit and Desna . G . Muir Mackenzie believed it to be " between the Bosna and Drina rivers , " while Florin Curta believed it to be central - eastern Bosnia . Klonimir was likely supported by the Bulgarians , which shows that Petar had bad relations with Bulgaria . However , Klonimir was unsuccessful , and the powerful Petar slew him . A little while afterwards , Petar was recognized as the ruler of Serbia by Bulgarian Tsar Symeon , resulting in a twenty - year peace and alliance . Aftermath . Petar ruled at peace with the Bulgars , though he was probably not happy with his subordinate position , and may have dreamed of reasserting his independence . His situation and the succession wars of the three branches of Vlastimir ' s sons was to play a key part in the coming Bulgarian – Byzantine War . However , according to " De Administrando Imperio " , Petar would have ruled under the suzerainty of Leo VI . Klonimir ' s son , Časlav , was sent with Bulgarian aid to conquer Serbia in 924 . The Bulgarians tricked him and annexed Serbia , until Časlav returned from exile in 927 after Symeon ' s death and asserted his rule over Serbia in a Byzantine alliance . On July 11 , 2006 , the Serbian government bought a Byzantine - styled seal in solid gold weighing 15 , 64 g , most likely belonging to Strojimir ( Klonimir ' s father ) , at an auction in Munich . It was presumably crafted outside Byzantium , and has a Greek inscription ( , " " God Help Strojimir " " ) and a patriarchal cross in the centre . It most likely dates to the second half of the 9th century , between 855 / 56 and 896 , when Klonimir tried to take the Serbian throne .