Early period: Imperial bodyguard

The Excubitors were founded by Emperor Leo I (r. 457–474) in c. 460 and were recruited from among the sturdy and warlike Isaurians, 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.^[2][3][4] 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.^[5][6][7]

The unit was headed by the count of the Excubitors (Latin: comes excubitorum; Greek: κόμης τῶν ἐξκουβίτων/ἐξκουβιτόρων, translit. komēs tōn exkoubitōn/exkoubitorōn), who was entirely independent of all other officials and subordinated only to the emperor himself.^[7] By virtue of his proximity to the emperor, the count of the Excubitors became an official of great importance in the 6th and 7th centuries. This post, which can be traced up to c. 680, was usually held by close members of the imperial family, often virtual heirs apparent.^[4][7][8] 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 (r. 491–518), his elevation to the throne.^[9][8] 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).^[10][11] He too would be succeeded by his own comes excubitorum, Maurice (r. 582–602).^[12] Under Maurice, the post was held by his brother-in-law Philippicus, and under Phocas (r. 602–610) by Priscus.^[8] Another powerful occupant was Valentinus, who secured it during the power struggles that accompanied the regency of Empress-dowager Martina in 641, before deposing her and her son Heraklonas and installing Constans II (r. 641–668) as emperor. Valentinus dominated the new regime, but his attempt to become emperor himself in 644 ended in his being lynched by the mob.^[13]

By the late 6th century, the count of the Excubitors held the highest court ranks, of patrikios and vir gloriosissimus.^[7] Apart from their duties as commander of the Excubitors, holders of the office now also undertook other functions such as recruiting troops and interrogating suspected traitors.^[7] The count of the Excubitors was even sent to lead campaigns.^[7] The power that went with the position, and the intrigues of men like Priscus and the would-be usurper Valentinus, doomed the post to eventual decline during the latter half of the 7th century,^[14] although it is likely that the post continued in existence into the 8th century, until the corps was reorganized.^[15]

The participation of the Excubitors in campaigns is well attested, such as in 598, when Emperor Maurice took them to defend the Anastasian Wall against the Avars.^[16] They served with Heraclius (r. 610–641) against the Sasanian Persians, and c. 650 some Excubitors appear as guards to Pope Martin I.^[17] During the later 7th century, like the Scholae before them, the Excubitors degenerated to a parade-ground unit that saw no active service.^[18] Indeed, it appears that during the 7th and early 8th centuries, the titles of excubitor and scribon were awarded as court dignities, paralleling the development of similar formerly military titles such as candidatus. This is evidenced by a large number of seals naming individual excubitors during this time, in stark contrast to the periods before and after, when the Excubitors are attested as an active military unit. Furthermore, in many of these seals, individual excubitores—as well as scribones—are shown to have conjointly held bureaucratic offices, while at least one seal is known of a certain George, who was both excubitor and a scholarius (a member of the Scholae).^[19]

Later period: Elite regiment

After being mentioned in a letter by Justinian II (r. 685–695, 705–711) to Pope John V in 687,^[20] the Excubitors as a corps disappear from the historical sources until they re-emerge, under a new commander, the domestic of the Excubitors (δομέστικος τῶν ἐξκουβίτων, domestikos tōn exkoubitōn) and in a new capacity, as one of the imperial tagmata, which comprised the elite professional central army established by Constantine V (r. 741–775) in c. 760.^[21][22] The tagmata were cavalry units,^[23] armed and equipped by the imperial arms factories to a higher standard than the provincial ('thematic') forces, likely including horse armour.^[24] As such the Excubitors were no longer a palace guard, but a unit actively engaged in military campaigns. At the same time, the tagmata, being loyal to the emperor's person, represented a counterbalance to the thematic armies of the provinces and constituted a powerful tool in implementing the iconoclastic policies pursued by Constantine V.^[25][26] Their original role as palace guardians was taken over by another, newly created tagma, that of the Vigla.^[27]

Nevertheless, the possibly first commander of the tagma, Strategios Podopagouros, was among the leaders of a failed plot against Constantine V's life in 765, and was executed after its discovery. This initiated a purge of the new units from suspected opponents of the Emperor's policies.^[28][29] By the 780s, following years of imperial favour and military victories under Constantine V and his son Leo IV the Khazar (r. 775–780), the tagmata had become firm adherents to the iconoclast cause.^[25][30] Within less than two months of Leo V's death in 780, Empress-regent Irene of Athens had to foil an attempt spearheaded by the Domestic of the Excubitors to place Constantine V's exiled second son, Nikephoros, on the throne,^[31] and in 785/86 Irene forcibly disarmed them and exiled some 1,500 tagmatic soldiers due to their resistance to the restoration of the icons.^[32][33][34]

At the same time, the tagmata were extensively employed in campaigns during this period: their participation is attested at least for Constantine V's 773 campaign against the Bulgars, and during the Abbasid invasion of Asia Minor in 782.^[27] Indeed, the historian John Haldon remarks that the retention of the tagmata by Irene, despite their iconoclastic bias, is testament to their effectiveness as a field force.^[34] The Scholae and the Excubitors nevertheless continued to play an active political role in the events of the following decades: in 792, they attempted to overthrow Irene's son, Constantine VI (r. 780–797), after the disastrous Battle of Marcellae against the Bulgars, and in 797, their support was crucial for Irene's overthrowing her own son and replacing him as sole ruler; and again, the two tagmata were crucial in the deposition of Irene herself in 802.^[35]

The Excubitors took part in the disastrous Pliska campaign in 811, when the Byzantine army was routed by Tsar Krum of Bulgaria (r. 803–814); the Domestic of the Excubitors fell in the field along with the other senior Byzantine generals, including Emperor Nikephoros I himself (r. 802–811).^[36] 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.^[37] The regiment also fought at the battles of Boulgarophygon in 896 and Acheloos in 917, both heavy defeats against the Bulgarians.^[38] In the expedition against the Emirate of Crete in 949, the Byzantine force included a contingent of over 700 Excubitors.^[38] In 958, the Excubitors participated in the repulsion of a Magyar raid.^[38]

The Excubitors took part in the failed Azaz campaign of 1030, where they were ambushed and dispersed by the Mirdasids, while their commander, the patrikios Leo Choirosphaktes, was taken captive.^[39] As with most of the Byzantine army, the tagmata of the capital atrophied during the mid-11th century, and many of them disappear in the turmoils of foreign invasion and civil wars that followed the destruction of the Byzantine field army in the Battle of Manzikert in 1071. The Excubitors are last attested in Anna Komnene's Alexiad, where they are recorded as participating at the Battle of Dyrrhachium against the Italo-Normans in 1081, under the command of Constantine Opos.^[40][41][42]

Early period

The internal structure of the regiment during its first centuries is obscure.^[43] Unlike the Scholae, which comprised several sub-units garrisoned throughout Bithynia (and occasionally in Thrace) as well as Constantinople,^[44] the Excubitors were a small and elite unit that served in the imperial palace itself and was intended exclusively to protect the emperor.^[45] From their foundation and throughout the early period of their existence, the Excubitors numbered 300 men.^[2][4] Originally recruited exclusively from Isaurians, the unit was eventually opened up to other ethnicities, but it is unclear how the new recruits were chosen.^[43] Based on the retention of late antique ranks in the middle Byzantine period, the Excubitors appear to have been structured similarly to the Scholae.^[46] Their arms and equipment are unknown, other than that they are recorded as carrying maces. Since they were a bodyguard unit intended to serve in the palace, they were most likely infantry.^[46]

The presence of officers called scribones in the corps has been controversial: John B. Bury and A. H. M. Jones both suggested that they were a separate, although possibly related, unit.^[43][47] Based on the presence of the scribones among the ranks of the later, middle Byzantine incarnation of the Excubitors, however, it is thought that the scribones were the subaltern officers of the count of the Excubitors.^[43] The historian Warren Treadgold speculates that they fulfilled a role similar to the regular cavalry decurions, commanding troops of 30 men each,^[6] but the scribones also appear in charge of administrative matters such as handing out pay to the soldiers,^[46] as well as more sensitive tasks such as delivering letters, making arrests, and preparing expeditions.^[43]

Later period

In its later incarnation as a tagma, the regiment (often called collectively τὸ ἐξκούβιτον, to exkoubiton or τὰ ἐξκούβιτα, ta exkoubita) was structured along the same standardized lines followed by the other tagmata, with a few variations in the titles of its officers.^[48][49][50]