Excubitors The Excubitors ( or " excubiti " , literally " those out of bed " , i . e . " sentinels " ; Greek : ) were founded in circa 460 AD as the imperial guard s of the early Byzantine emperors . Their commanders soon acquired great influence and provided a series of emperors in the 6th century . The Excubitors fade from the record in the late 7th century , but in the mid - 8th century , they were reformed into one of the elite tagmatic units , the professional core of the middle Byzantine army . The Excubitors are last attested in 1081 AD . History . The Excubitors were founded in Late Antiquity by Emperor Leo I ( reign ed 457 – 474 ) circa 460 and numbered 300 men , often recruited from among the sturdy and warlike Isauria ns , as part of Leo ' s effort to counterbalance the influence of the " magister militum " Aspar and the large Germanic element in the East Roman army . Unlike the older palace regiments of the " Scholae Palatinae " , which were under the control of the " magister officiorum " and eventually degenerated to parade - ground formations , the Excubitors long remained a crack fighting force . Unlike the " Scholae " , which were garrisoned throughout Thrace and Bithynia , the Excubitors were billeted in the imperial palace itself and formed practically the only garrison of Constantinople in the 6th century . Their high status is further illustrated by the fact that both officers and ordinary Excubitors were often sent for special missions , including diplomatic assignments . The unit was headed by the Count of the Excubitors ( ; , " komēs tōn exkoubitōn / exkoubitorōn " ) , who , by virtue of his proximity to the emperor , became an official of great importance in the 6th and 7th centuries . This post , which can be traced up to circa 680 , was usually held by close members of the imperial family , often virtual heirs apparent . Thus it was the support of his men that secured Justin I ( r . 518 – 527 ) , who held the post at the time of the death of Anastasius I , his elevation to the throne . Similarly , Justin II ( r . 565 – 578 ) relied on the support of the Excubitors for his unchallenged accession ; their count , Tiberius , was a close friend who had been appointed to the post through Justin ' s intervention . Tiberius was to be the Emperor ' s right - hand man throughout his reign , eventually succeeding him as Tiberius II ( r . 578 – 582 ) . He too would be succeeded by his own " comes excubitorum " , Maurice ( r . 582 – 602 ) . Under Maurice , the post was held by his brother - in - law Philippicus , and under Phocas ( r . 602 – 610 ) by Priscus . The power that went with the post , and the intrigues of men like Priscus and , in the early 640s , the would - be usurper Valentinus , doomed the post to emasculation and eventual eclipse during the latter half of the 7th century . After a lapse towards the end of the 7th century and the first half of the 8th century , the Excubitors reappear in historical sources , under a new commander , the Domestic of the Excubitors ( , " domestikos tōn exkoubitōn / exkoubitorōn " ) and in a new capacity , as one of the imperial " tagmata " , the elite professional central army established by Constantine V ( r . 741 – 775 ) . As one of the " tagmata " , the Excubitors were no longer a palace guard , but a unit actively engaged in military campaigns . At the same time , they were created as a counterbalance to the thematic armies and constituted a powerful tool in implementing the iconoclastic policies pursued by Constantine V ; their allegiance was so strong that pro - iconodule regent Irene had to forcibly disarm them in 786 . The Domestics were originally of strikingly low court rank ( mere " spatharioi " ) , but they gradually rose to importance : while in the " Taktikon Uspensky " of circa 842 the Domestic of the Excubitors ranks behind all the thema tic " stratēgoi " , in the " Klētorologion " of 899 , the Domestic is shown as superior to the " stratēgoi " of the European themes and even to the Eparch of Constantinople . At the same time , their rank rose to that of " prōtospatharios " and even " patrikios " . The most prominent Domestic of the Excubitors of the period was Michael II the Amorian ( r . 820 – 829 ) , whose supporters overthrew Emperor Leo V the Armenian ( r . 813 – 820 ) and raised him to the throne . In the latter half of the 10th century , probably under Romanos II ( r . 959 – 963 ) , the regiment , like the senior " tagma " of the " Scholae " , was split in two units , one for the West and one for the East , each headed by a respective Domestic . As with most of the " tagmata " , the regiment did not survive the great upheavals of the later 11th century , when foreign invasion and constant civil war s destroyed much of the Byzantine army . The last mention of the Excubitors occurs in Anna Komnene ' s " Alexiad " , where they are recorded for the last time as participating at the Battle of Dyrrhachium in 1081 under Constantine Opos . Structure . The internal structure of the original " excubitores " regiment is unknown . It is known that it was a cavalry unit and that it had officers called " scribones " . The historian Warren Treadgold speculates that they fulfilled a role similar to the regular cavalry decurion s , commanding troops of 30 men each , but John B . Bury suggested that the " scribones " , though associated with the " excubitores " , remained a separate corps . In its later incarnation as a " tagma " , the regiment ( often called collectively ) was structured along standardized lines followed by the other " tagmata " , with a few variations . The " domestikos " was assisted by a " topotērētēs " ( Greek : τοποτηρητής , lit . " placeholder " , " lieutenant " ) and a " chartoularios " ( Greek : χαρτουλάριος , " secretary " ) . The regiment itself was divided into at least eighteen " banda " , probably each commanded by a " skribōn " ( Greek : σκρίβων ) . Each of them was further divided into sub - units headed by a " drakonarios " ( Greek : δρακονάριος , deriving from the late Roman " draconarius " ) , and included three classes of standard - bearers who functioned as junior officers : the " skeuophoroi " ( Greek : σκευοφόροι , " standard carriers " ) , " signophoroi " ( Greek : σιγνοφόροι , i . e . signifer s ) and " sinatores " ( Greek : σινάτορες , from the late Roman rank of " senator " ) . There were also the usual messengers ( Greek : μανδάτορες , " mandator es " ) under a " prōtomandatōr " , some of whom were also termed " legatarioi " ( Greek : λεγατάριοι ) . The size of the " tagma " of the Excubitors and its subdivisions can not be determined with certainty ; as with the other " tagmata " , scholars are of differing opinions regarding its numerical strength . Drawing on the lists of officers and accounts of Arab geographers Ibn Khurdādhbah and Qudāmah , historian Warren Treadgold maintains an establishment strength of circa 4 , 000 men , which for the " Scholae " and the Excubitors rose to circa 6 , 000 with the division of the regiments in the mid - 10th century . Other scholars , most prominently John Haldon , have revised estimates to some 1 , 000 men for each " tagma " .