Justin ( consul 540 ) Flavius Mar ( cianus ? ) Petrus Theodorus Valentinus Rusticius Boraides Germanus Iustinus , simply and commonly known as Justin ( , ; circa 525 – 566 ) , was an East Roman ( Byzantine ) aristocrat and general . A member of the Justinian Dynasty and nephew of Emperor Justinian I ( r . 527 – 565 ) , he was appointed as one of the last Roman consuls in 540 , before going on to assume senior military commands in the Balkans and in Lazica . He fought against the Slavs , the Sassanid Persians and supervised the Byzantine Empire ' s first contacts with the Avars . At the time of Justinian ' s death , he was seen as a probable successor , but was beaten to the throne by his cousin , Justin II ( r . 565 – 578 ) , who exiled him to Egypt , where he was murdered . Biography . Early life and campaigns . Justin was born around 525 , the eldest son of Germanus and his wife Passara . Germanus was a cousin of the Byzantine emperor Justinian I ( r . 527 – 565 ) and thus a member of the wider Justinian dynasty and cousin to Justinian ' s successor , Emperor Justin II ( r . 565 – 578 ) . In 540 , he was named ordinary consul at a very young age ; he is illustrated as beardless in his consular diptych , and is still mentioned as a " young man " by Procopius nine years later . At this point , he already held the title of " vir illustris " and the honorary office of " comes domesticorum " . In the same year , he accompanied his father to the East against the Sassanid Persians , but saw no action . In 549 , he was instrumental in the revelation of the plot to overthrow Emperor Justinian by the Armenian general Artabanes and his associates . The conspirators intended to assassinate Emperor Justinian and his favourite general Belisarius , and raise Germanus to the Byzantine throne . Notified of their intentions , Justin informed his father , who then told Marcellus , the Count of the Excubitors , leading to the plotters ' arrest . In 550 , together with his younger brother Justinian , he joined their father in his expedition against Ostrogoth Italy , but Germanus died suddenly in the autumn of 550 , before the army had left the Balkans , where it was assembling . After this , Justinian and Germanus ' s son - in - law , John , led the army towards Salona ( modern Split , Croatia ) , where the eunuch Narses assumed command in late 551 . In early 551 , Justin was attached to a force under the eunuch Scholasticus that campaigned against a Slavic raid in the eastern Balkans . The Byzantines were initially defeated near Adrianople but went on to score a victory , after which the Slavs left Byzantine lands . In early 552 , Justin and Justinian were placed at the head of another expedition against a Slavic raid against Illyricum , but their forces were too small to confront the raiders directly . Instead , the brothers had to content themselves with harassing them . Shortly after , they were ordered north to assist the Lombards against the Gepids along with Aratius , Suartuas , and Amalafridas , but the Byzantines were detained from advancing too far north by the need to suppress religious strife in the city of Ulpiana . High command in Lazica and the Danube . In 554 , now experienced in military affairs , Justin was sent east to Lazica to join the Byzantine forces under Bessas , Buzes , and Martin . His first encounter with the Persians was unsuccessful . Along with Bessas , Justin and his troops were encamped at the plain of Chytropolia , near the strategically important fortress of Telephis , which was held by Martin . The Persian general Mihr - Mihroe , however , succeeded in dislodging Martin from Telephis . Martin withdrew to join the other two generals at Chytropolia , but there again the Byzantine army , too slow to take up position , was forced to flee in disarray before the advancing Persians , retreating along the Phasis river to the fortified island of Nesos ( Νήσος , Greek for " island " ) . Bessas was dismissed from high command as " magister militum per Armeniam " after this debacle , and succeeded by Martin with Justin as his second in command . Justin was ignorant of Martin ' s intention to assassinate their ally , the Lazic king Gubazes II ; when he learned of the deed , he was shocked , but did not reprimand Martin because he believed – wrongly – that the murder had been carried out at the orders of Emperor Justinian . The Byzantines then launched an attack on the Persian fort of Onoguris , but they were forced to abandon it at the unexpectedly quick arrival of Persian relief forces under Nachoragan . In spring 556 , Justin was with the rest of the Byzantine forces at Nesos , when Nakhoragan invaded western Lazica , making for the town of Phasis . The Byzantines hastily departed for the town , managing to reach it before the Persian army and then proceeded to successfully defend it during a prolonged siege . Following this success , in early 556 Justin returned to Nesos to guard it together with Buzes , while the rest of the army marched against the Misimians , a tribe that had recently allied itself with the Persians and killed the Byzantine general Soterichus . Justin ' s only activity during this time was to dispatch one of his officers , Elminzur , to capture Rhodopolis ( modern Vardistzikhe ) with 2 , 000 cavalry . In the next year , a general truce was agreed , which was finalized into a peace treaty in 562 . Soon after , an imperial investigation into Gubazes ' s murder brought to light Martin ' s culpability . His military successes spared his life , but cost him his command ; he was replaced as " magister militum per Armeniam " by Justin in spring 557 . It was in this capacity that in late 557 Justin received the first Avar embassy to the Byzantine Empire . The Avars , who had fled their ancestral lands in Central Asia before the rise of the Göktürks , asked for imperial protection and for land to settle on . Justin forwarded them to Constantinople , where they arrived in December . Turned away from the Empire and towards the plains of the Ukraine by Justinian , the Avars defeated enemy after enemy and eventually reached the northeastern bank of the Danube in 561 / 562 . There they again encountered Justin , who had just been transferred to the command of the " quaestura exercitus " covering the lower Danubian " limes " ( the " Limes Moesiae " ) . At this time , the Avars demanded to settle in Byzantine imperial territory in Scythia Minor , whose defences had been devastated by a recent Kotrigur invasion led by Zabergan . Here , Justin played a crucial role and gained great fame , by learning of the Avars ' intentions and warning Justinian . Consequently , the Avar embassy to Constantinople was detained while the Byzantine defences were put in order . With Justin continuing to maintain a careful watch over the Danube river , the Avars contented themselves with the annual subsidy paid by Byzantium , and left the Empire in peace for some years to come . Exile and death . At the time of Emperor Justinian ' s death in 565 , due to his titles and reputation as a commander , as well his army ' s proximity to the imperial capital , he was the leading contender for the vacant throne , along with his cousin Justin , the " curopalates " . The latter , however , was already present at Constantinople , and could count on the support of the Byzantine Senate , and especially of Patriarch John Scholasticus and the Count of the Excubitors Tiberius ( the future Tiberius II ) , whom he had helped secure his post . Thus Justin was hastily elevated to the throne on the same day that Justinian died . According to the contemporary historian Evagrius Scholasticus , the two Justins had reached an agreement whereby whoever would be crowned emperor would make the other the " second man " in the empire . When Justin II recalled his cousin to Constantinople , it seemed that this was the reason . The general was warmly received at first , but soon the new emperor began to make accusations against him , dismissed his bodyguard and placed him under house arrest , before sending him to exile in Alexandria , ostensibly as the new augustal prefect of Egypt . There , he was murdered in his sleep , ostensibly because he was plotting to seize the throne , and his head was cut off and brought to Constantinople . In reality , he was too great a threat to the new emperor to be left alive ; the Visigoth chronicler John of Biclaro explicitly attributes the murder to Justin II ' s wife , the Empress Sophia .