russian russian bulgarian hungarian 14th century bulgarian military leader russian origin served bulgarian prior joining armed forces second bulgarian empire russian military commander service hungarian governor russian rose high rank bulgarian military wake accession throne charge bulgarian defence prolonged ultimately successful byzantine siege city involved failed bulgarian attempt capture byzantine capital constantinople probably taking turbulent events surrounded followed death russian mentioned representative early years siege bulgarian historian russian born centred modern western ukraine hypothesis based ties hungary western neighbour hungarian sources notice russian named ally ban nobles opposed rule land south governed bulgaria supporter hungarian king established authority suppressed rebellion russian fled entered service thought joined commander subordinate personal forces consisted hungarians presumably russians hungarian scholar supports identification russian chronicles historian points lack clear evidence large time span identification proposed considered arrived bulgaria fleeing conquest like russian bulgarian service way right hand man hungarian named accession bulgarian throne meant russian assumed elite rank bulgarian military hierarchy title borrowed byzantium title held second command army approximate western marshal year dispatched city recently conquered bulgaria decades byzantine rule thousand strong cavalry force possibly hungarians thousand defend city byzantine raids task assisted deputy time known byzantium military commander bulgarian forces commanded russian managed withstand month siege undertaken iii byzantine throne bulgarian ally attempts capture city byzantines employed german specialists construct siege machine fired bulgarian defenders despite elaborate siege tactics summer retained city launched raids nearby byzantine held fortresses modern lost byzantines soon forces leaving city meet bulgarian garrison replace pro byzantine inhabitants opened city gates let covert byzantine detachment anti byzantine plot later career loss profound effect career remained royal favourite tasked defence great palace constantinople residence emperor facing imminent defeat hands grandson emperor iii protracted civil war guard requested assistance bulgarian emperor sent russian horsemen constantinople aid words byzantine historian actual intentions use men suitable moment bulgarian guard arrest emperor hold palace allowing large army mercenaries constantinople accordance plan cavalry approached constantinople waited army plot uncovered spies fearing imperial ambitions wrote rival grandfather accept capital stuck plan signed oath come peace persuade byzantines promptly retreated bulgarian territory receiving order role final years reign rule uncertain mentioned sources pertaining period high ranking position leads took july serbian victory bulgaria paved way serbian dominance balkans century killed battle succeeded son believes russian bulgarian nobles ousted weak placed throne probable russian took bulgarian victory byzantium recorded representative peace negotiations followed assessment russian held high regard writer later byzantine emperor likely personally faced battle history calls man skilled strategy referred bulgaria people writings czech historian prominent researcher bulgarian history clear cut figure bulgarian military leader age eyes despite foreign origin russian considered mercenary bulgarian nobility emperor trusted commander
Ivan the Russian