Comentiolus Comentiolus ( , " Komentiolos " ; died 602 ) was a prominent Eastern Roman ( Byzantine ) general at the close of the 6th century during the reign of Emperor Maurice ( r . 582 – 602 ) . He played a major role in Maurice ' s Balkan campaigns , and fought also in the East against the Sassanid Persians . Comentiolus was ultimately executed in 602 after the Byzantine army rebelled against Maurice and Emperor Phocas ( r . 602 – 610 ) usurped the throne . Biography . Nothing is known of Comentiolus ' s early life , except that he hailed from Thrace . He first appears in 583 , as an officer ( " scribon " ) in the " Excubitores " , the imperial bodyguard , when he accompanied a Byzantine embassy to Bayan I ( r . 562 – 602 ) , the khagan of the Avars . According to the historian Theophylact Simocatta , he enraged the khagan with an outspoken statement , and was briefly imprisoned . It is likely that the close trust he shared with Maurice dates from the latter ' s time as commander of the " Excubitores " , before his ascension to the throne . Throughout his career , Comentiolus would be loyal to Maurice , and the Emperor would watch over his protégé ' s career . The next year , after a truce with the Avars had been arranged , he was appointed in charge of a brigade ( " taxiarchia " ) operating against the Slavic tribes that raided Thrace and had penetrated as far as the Long Walls of Anastasius , Constantinople ' s outer defensive system . Comentiolus defeated them at the river Erginia , near the Long Walls . As a reward for this success , he was appointed " magister militum praesentalis " in 585 . On this occasion , or perhaps a bit later ( possibly in 589 ) , Comentiolus was raised to the supreme title of " patricius " . In the summer of 585 , he defeated again a large force of Slavs , and in 586 he was placed in charge of the war against the Avars , after they broke the treaty . In 587 , Comentiolus assembled a 10 , 000 strong army at Anchialus . He prepared an ambush for the Avar khagan in the Haemus mountains , but it failed . In 589 , Comentiolus appears to have been appointed as " magister militum Spania e " : an bearing his name has been found in Carthago Nova , but it may have been erected by a namesake . At any rate , by the autumn of 589 he was back in the East , replacing Philippicus in command of the eastern army in the ongoing war against the Sassanid Persians . His army defeated the Persians at the Battle of Sisauranon in the same year and unsuccessfully tried to recapture Martyropolis . In the spring of 590 , however , while at his headquarters at Hierapolis , he received an unexpected guest : the legitimate Persian king , Khosrau II ( r . 590 – 628 ) , who had fled to Byzantine territory to seek support against the usurper Bahram VI Chobin ( r . 590 – 591 ) . Emperor Maurice decided to support the exiled monarch , and assembled an army to restore Khosrau to his throne . Comentiolus was initially slated to lead this force , but after Khosrau complained of Comentiolus being disrespectful towards him , he was replaced as commander of this by Narses . Comentiolus still took part in the subsequent campaign as commander of the army ' s right wing . The restored Persian king repaid Roman assistance with a treaty which put an end to the war that had lasted almost 20 years , and ceded back all cities lost in Mesopotamia , as well as most of Armenia , to the Romans . This favourable peace meant that Byzantium ' s forces could now be concentrated against the Avar and Slav incursions in Illyricum . In 598 , Comentiolus was sent back into action against the Avars , probably with the position of " magister militum per Thracias " . After a heavy defeat caused by his neglect to properly array his forces for battle , his army was scattered and he himself fled to Constantinople , where he faced charges of treason . These were dropped at the Emperor ' s request , and Comentiolus was reconfirmed as general for Thrace . His subsequent record is not very distinguished , but this may be more due to the negative bias of Simocattes , our main primary source , towards him and his co - general Peter , rather than because of inability or inaction on his part . At any rate , when the army rebelled against Maurice in 602 , Comentiolus was entrusted with the defence of the Walls of Constantinople . When Phocas eventually took the city , he was one of the first adherents of the old regime to be executed .