1. Historical context
The protagonists of the rebellion of Thomas, described as ‘the Slav’ in recent scholarship due to his origins,1 are closely connected with him since July of 803. The of the theme of Anatolikon, Bardanes the so-called ‘Turk’, had rebelled against Emperor Nikephoros I with the cooperation of a group of devoted military men: Leo the Armenian (Leo V), Michael of Amorion and Thomas.2 Contrary to the first two, who finally joined forces with Nikephoros and received high offices, Thomas remained faithful to Bardanes, which resulted in his disappearance from the political fore following the failure of the rebellion.3 He reappeared when his former companion Leo the Armenian ascended on the imperial throne, honouring him with the office of of the , a position Thomas maintained throughout Leo’s reign, residing at the base of his unit, in the theme of Anatolikon. In the early hours of Christmas day of 820, Leo V was murdered, after a conspiracy of followers of Michael of Amorion, and the latter acceded to the throne as Michael II. In order to avenge the murder of his friend and emperor, and punish the culprit, with whom he always had personal differences, but also to pursue his own political ambitions, Thomas refused to recognize the new emperor and immediately rebelled against him, accusing Michael as a usurper and promoting himself as a guardian of imperial legitimacy.4
The circumstances during the outbreak of the rebellion were favourable. Although the office Thomas held was not the highest-ranking in the hierarchy of the theme of Anatolikon, the fact that his military base was in the theme’s seat, the city of Amorion, afforded him significant power. Furthermore, his long military career, already since Bardanes’ time, and Thomas’ military and intellectual talents had made him especially popular among the soldiers of Asia Minor. Thomas’ popularity becomes even more important if we consider that during the same period Michael II, a man largely obscure up to then and disagreeable due to his reported vices and of dubious martial prowess, had not had enough time to become established in the minds of his subjects as emperor and founder of a new dynasty. Under these circumstances, Thomas’ rebellion did not really threat an established imperial legitimacy, as in the case of similar rebellions in the history of the Byzantine Empire. The fact, however, that it broke out immediately after Michael II’s coronation at Constantinople made it appear more of a clash between two equal military officials over the throne. Thomas’ strong and familiar to the citizens of Asia Minor personality, coupled with the fact that he had no part in the murder of Leo V who also enjoyed wide support in the area, worked to his advantage. The social and economic conditions that prevailed in Asia Minor during that time also influenced positively the way the people viewed the outbreak of the rebellion.5 More specifically, there was intense discontent among the farmers because of the onerous taxation imposed by the distant capital, but also because of the aberrations of the state officials against them. This atmosphere favoured the direct support of a rebellion that turned against the central administration, especially one that was led by a familiar and popular official.6
2. The rebellion of Thomas
2.1. Outbreak of the rebellion in Asia Minor
Immediately after December 25, 820 the tourmarch of the Foederati Thomas the Slav rebelled against Michael II and was proclaimed emperor by the troops of the theme of Anatolikon. Within a short period he had won the support of most of the thematic troops of Asia Minor, as well as that of the Kibyrrhaioton fleet.7 He was also joined by state officials, among which were local tax collectors, who offered him the income resulting from the taxes in their areas. Only Katakylas and Olbianos remained faithful to Michael II - they were the strategoi of the themes of Opsikion and of Armeniakon respectively.8 Apart from the support of the thematic army, Thomas aimed at securing military help from the populations residing northeast of the imperial borders (Iberians, Armenians and Abkhazians).9 Michael II, who followed the developments in Asia Minor from Constantinople, ordered the troops loyal to him to move against Thomas.10 In the battle that followed the forces of Michael II were turned to flight, while Thomas penetrated as far as Chaldia, which he placed under his control. Taking advantage of this internecine conflict, the Arabs intensified their land and sea raids against Asia Minor, which forced Thomas to temporarily postpone his offensive, as he had to deal dynamically with the danger facing the areas that supported him and could not successfully wage war on two fronts at the same time. Thus, probably in the spring of 821, Thomas led a campaign against the Arab lands,11 at the same time dispatching an embassy to the Arab al-Mamūn (813-833).
The negotiations that ensued finally led to the creation of an alliance between Thomas and the Arabs against Michael II.12 Thomas then travelled to Antioch of Syria, where the Orthodox Patriarch Job crowned him emperor, with the consent of al-Mamun. Thomas also adopted a young man, to whom he gave the name Konstantios, so as to have an heir. Controlling the largest part of the coasts of Asia Minor, Thomas built a fleet of warships and transports to reinforce the thematic fleet that awaited his orders at Lesbos. Leading his land army he moved towards Abydos, aiming to join forces with his fleet and transport his troops to Thrace, in order to assail Constantinople, as only the capture of the capital could legitimize his ascend to the throne, both on a real and a symbolic level. While Thomas was in Abydus, Konstantios joined battle with Olbianos, was defeated and killed. Michael II, who still enjoyed the support of the and of the imperial fleet, was keen to retain the favour of the themes that had not sided with Thomas at the outset, i.e. the themes of Armeniaca and Opsikion. Thus as a reward for their loyalty he cut the sum their subjects had to pay for the tax for that particular year by half. When Thomas’ activities on the northern coasts of Asia Minor revealed that he was planning to attack Constantinople through Thrace, Michael II attempted to secure the allegiance of the Thracian cities and strengthened their defences with fortification works so that they could withstand Thomas’ offensive. He also recalled the strategoi Olbianos and Katakylas with troops from their themes, reinforced the walls of Constantinople and barred entrance to the Golden Horn inlet by pulling a huge chain across it.
2.2. Abortive siege of Constantinople
Thomas sailed from Abydus to Thrace in October or November of 821. The inhabitants greeted him with enthusiasm and many willingly enlisted in his army.13 A combined assault was to be launched on Constantinople by land and sea simultaneously. Thomas appointed Gregorios Pterotos14 as commander of the land forces, while the entire rebel fleet sailed from Abydus to Constantinople. Meeting no resistance from the imperial warships, the fleet broke through the chain and entered the Golden Horn inlet, up to the estuary of the Barbyses River, awaiting Thomas’ arrival. Thomas marched off to Constantinople leading the rest of his land forces, accompanied by a former monk named Anastasios, whom he adopted in place of the deceased Konstantios. Thomas’ hopes that the inhabitants of the capital would cower seeing the size of his forces and immediately surrender the city were disproved. Thus he was forced to make camp north of the city, near the monastery of Ss Cosmas and Damian. From there he dispatched troops to capture the coasts from Thrace to the Pontus and, in December of 821, he launched a naval and land offensive against Constantinople. The weather conditions, however, hampered his military operations and thus he decided to temporarily postpone them. Michael II took advantage of this and reinforced Constantinople’s defences with forces troops the themes of Armeniakon and of Opsikion. In the spring of 822 Thomas resumed his offensive on Constantinople with greater intensity, failing however to achieve the desired results. Thus, many of his soldiers begun defecting to Michael II, who had promised amnesty to them. Gregorios Pterotos accompanied by a small military force also tried to defect to the enemy camp. Thomas, however, realized this soon enough, arrested Gregorios and put him to death. On the occasion of this success Thomas declared that he had beaten Michael II’s forces on both land and sea and requested that the theme of Greece, the Peloponnese and the Aegean islands provide him with more warships so as to capture Constantinople. Indeed, in the summer of 822 new ships arrived and harboured in the port of Byridoi, north of the Propontis.15 Yet, before this fleet had a chance to join with the rest of the rebel forces it came under attack by the imperial fleet, resulting in most of the ships being destroyed by , or captured by the enemy – only a small portion managed to safely reach their destination. Notwithstanding this success, Michael II still did not possess enough troops to launch an attack and finally lift the siege of Constantinople. Thus, calling upon a treaty signed during the reign of Leo V, he asked the Bulgarian Omurtag to attack Thomas.16 In November of 822 the Bulgarians invaded the Byzantine lands, forcing Thomas to move against them with his entire army. In the battle that was joined in the plain of Kedouktos, situated between Heraclea and Selymbria, both armies suffered heavy casualties. The Bulgarians retreated to their lands, but Thomas was unable to return to Constantinople to continue his siege for wintertime was advancing and he no longer possessed a fleet: his last ships had surrendered to Michael II while he was fighting the Bulgarians. Thus he set up camp in the plain of Diabasis, approximately 40km west of the capital.17
2.3. Suppression of the rebellion
When in the spring of 823 Thomas resumed his offensive making raids into Thrace, Michael II decided to campaign against him, accompanied by forces from the themes of Armeniakon and of Opsikion. In the battle that was fought in the plain of Diabasis (April or early May of 823) Thomas’ troops, weary of the three-year war, took to flight. Many surrendered to Michael II; others, under Anastasios, Thomas’ adopted son, sought refuge at Bizye and in other fortresses of Thrace, while a part of the army under Thomas sought refuge in Arcadiopolis.18 Michael II pursued Thomas and laid siege to Arcadiopolis for five months, a period during which the people managing to escape the siege sought refuge at Bizye. Finally, in mid-October of 823 the exhausted by the famine inhabitants of Arcadiopolis conspired against Thomas and handed him to the emperor, who had him mutilated and then killed. When this happened, the inhabitants of Bizye handed in Anastasios, who met a similar fate. Although the rebellion of Thomas had been decisively crushed, some of his followers in Thrace, taking cover in Panion and Heraclea, continued to oppose Michael II.
An earthquake that occurred in February of 824 destroyed the walls of Panion forcing those inside it to surrender, while the damage caused to the walls of Heraclea facilitated its capture soon after by the imperial forces. Early in March of 824 Michael II returned to Constantinople victorious, where he made a triumph, parading the chained followers of Thomas in the Hippodrome. Still, two of Thomas’ officials in Asia Minor, Choireus and Gazarenos Koloneiates, refused the high offices offered to them by Michael II to recognize him as emperor and continued to launch raids, the former using Kaballa (northwest of Ikonion) as his staging grounds, the latter using Saniana (southeast of Ankara). Michael II finally convinced the inhabitants of these two fortresses to not readmit Choireus, Gazarenos Koloneiates and their troops upon their return from yet another raid. To save themselves, they were forced to move towards the territory of the Arabs, but they were intercepted by the forces of Michel II and were put to death.
The rebellion of Thomas the Slav, which is the most important event in the internal political scene during the reign of Michael II, weakened the Byzantine Empire at all levels. It developed into a fully-fledged civil war which lasted three whole years, specifically because the two sides were more or less evenly matched in terms of their military forces and thus could not strike a decisive blow to their opponent. The fleet of the empire (thematic as well as imperial) suffered the greater losses. Notwithstanding the fact that the casualties among the land forces were not so great, the thematic army was also weakened by the protracted warfare. All these negatively impacted the defensive abilities of the Byzantine Empire which would soon be unable to stop the capture of Crete by the Arabs of Spain, as well as the African Arabs’ invasion in the Byzantine lands of Sicily in 827. These failures in the area of the Mediterranean forced Michael II and his successor Theophilosto focus their attention on the defence of Asia Minor against the attacks of the Eastern Arabs. The consequences on the financial and social level were also grave. The extensive destruction reeked upon various areas of the empire, and mainly Thrace, due to the prolonged presence of large military contingents, the armed clashes and the raids threw their economic life into disarray. The religious policy Michael II followed was largely formulated in the aftermath of Thomas’ rebellion, for the adoption of Iconoclasmby himwould prove that he was a true heir to Leo V, who also opposed the veneration of the icons.19 With respect to foreign diplomacy, Thomas’ rebellion firmly established an alliance between the Byzantines and the Bulgarians that continued in the following decades. Finally, apart from the exemplary punishment of the rebel and his adopted son, as well as the execution of some of his followers, Thomas’ rebellion did not have grave consequences on individual persons, as the victorious Emperor Michael II was rather merciful towards his vanquished foes, sentencing to exile only those he deemed most dangerous.
1. According to the Chronography of the continuators of Theophanes, Bekker Ι. (ed.), Theophanes Continuatus (Bonn 1838), p. 50, 19-21, Thomas descended from Slav settlers of Asia Minor. On the contrary, according to a passage of Joseph Genesios, Lesmiiller-Werner, A. — Thurn, I. (ed.), Iosephi Genesii Regum Libri Quattuor (Corpus Fontium Historiae Byzantinae 14, Berlin - New York 1978), he was of Armenian descent (p. 7.14-15); in another passage he appears as of Scythian origin (p. 23.89). In the French edition of Vasiliev, A.A., Byzance et les Arabes 1: La dynastie d'Amorium (820- -867) (Corpus Bruxellense Historiae Byzantinae I, Bruxelles 1968), p. 26, is it said that Thomas was of Armenian descent, although the Russian original makes no such claim. At any rate, according to the prevalent view he descended from Slav settlers of Asia Minor in the area of the Gazourou Lake in the Galatian Pontus, which during that period belonged to the theme of Armeniakon. On this see the detailed arguments in Lemerle, P., "Thomas le Slave", Travaux et Memoires 1 (1965), p. 284. Recently Belke, Κ. - Restle, Μ., Galatien und Lykaonien (Tabula Imperil Byzantini 4, Wien 1984), p. 218, have tentatively argued that Thomas originated from the area of Lake Pousgouse, which was located between the provinces of Pisidia and Lycaonia.
2. The Byzantine forces mention that Bardanes, accompanied by the three men and before he revealed any intentions to rebel, visited a monk close to Philomelion, famous for his prophetic powers, and revealed his plans to him. It is said that the monk not only foresaw the final failure of the rebellion, but also the future of his three followers. See Μαυρομάτη-Κατσουγιαννοπούλου, Σ., “Η επανάσταση του στρατηγού Βαρδάνη στις σύγχρονες και μεταγενέστερες αφηγηματικές πηγές”, Βυζαντινά 10 (1980), pp. 220-224.
3. According to Lemerle, P., "Thomas le Slave", Travaux et Memoires 1 (1965), p. 284, Thomas’ activities during this period remain unknown. A testimony in the Byzantine sources that he sought refuge among the Arabs is a later fabrication designed either to discredit the rebel’s personality, or to attribute his impressive exploits to the Arabs, or, finally, to obscure the circumstances in which Michael II rose to the throne. This view is shared by Χριστοφιλοπούλου, Αικ., Βυζαντινή Ιστορία 2.1: 610-867 (Θεσσαλονίκη2 1993), p. 195. Treadgold, W. Τ., The Byzantine Revival 780-842 (Stanford 1988), p. 229, mentions that Thomas served in the tourma of the Foederati following the failure of Bardanes’ rebellion in 803 and until Leo V appointed him head of this tourma in 813. On the contrary, according to Jenkins, R.H.J., Byzantium: The Imperial Centuries (AD 610-1071) (London 1966), p. 141, Thomas spent this period in exile among the Arabs; Vasiliev, A.A., Byzance et les Arabes 1: La dynastie d'Amorium (820- -867) (Corpus Bruxellense Historiae Byzantinae I, Bruxelles 1968), p. 26-30, believes that Thomas sojourn among the Arabs lasted from 797 until the end of Leo V’s reign.
4. According to Lemerle, P., "Thomas le Slave", Travaux et Memoires 1 (1965), p. 284, the possibility that Thomas launched his rebellion even before Leo V’s murder is yet another fabrication found in the Byzantine sources, a result of Michael II’s propaganda. Furthermore, Treadgold, W.T., The Byzantine Revival 780-842 (Stanford 1988), p. 228, notes that Michael II could rely on this propaganda because Thomas was proclaimed emperor within such a short period of time after Michael’s coronation at Constantinople. On the contrary, Jenkins, R.H.J., Byzantium: The Imperial Centuries (AD 610-1071) (London 1966), p. 141, believes it is likely that he rebellion broke out before Leo V’s murder.
5. Some hold that, in order to enlist supporters, Thomas took advantage of the iconoclastic dispute, declaring himself a champion of the iconophiles. According to the Byzantine sources, he claimed to be the deposed Emperor Constantine VI, who was still alive and had not been blinded by his mother, Empress Eirene. See Vasiliev, A.A., Byzance et les Arabes 1: La dynastie d'Amorium (820-867) (Corpus Bruxellense Historiae Byzantinae 1, Bruxelles 1968), p. 23; Jenkins, R.H.J., Byzantium: The Imperial Centuries (AD 610-1071) (London 1966), pp. 141-142; Ostrogorsky, G., Geschichte des byzantinischen Staates (Munchen 1963), translated into Greek by Ι. Παναγόπουλος, Ιστορία του Βυζαντινού κράτους 2 (Αθήνα 1989), p. 77; Hild, F. - Restle, M., Kappadokien (Kappadokia, Charsianon, Sebasteia und Lykandos) (Tabula Imperii Byzantini 2, Wien 1981), p. 77. Lemerle, P., "Thomas le Slave", Travaux et Memoires 1 (1965), p. 283-284, considers the testimony of the sources unreliable and attributes it to the later propaganda of Michael II against Thomas. Furthermore, he argues that the correlation of Thomas’ rebellion with the second phase of the iconoclasm is unfounded, because if it is accepted it would lead to a series of acute contradictions: if Thomas really appeared to the subjects as a supporter of the icons, how can we justify the fact that he requested the help of the ‘godless’ Arabs, that he received no help during the first phase of the iconoclasm from the iconophile themes of Armeniakon and Opsikion and that he rebelled because of the murder of the iconoclast Leo V. Lemerle, however, does not preclude the possibility that an informal rumour circulated concerning Thomas’ iconophile stance, because of which some people would have been inclined to join him. Most recent scholars follow Lemerle’s outline on this. See Χριστοφιλοπούλου, Αικ., Βυζαντινή Ιστορία 2.1: 610-867 (Θεσσαλονίκη2 1993) 197; Kaegi, W.E., Byzantine Military Unrest 471-843 (Amsterdam 1981), p. 267; Treadgold, W.T., The Byzantine Revival 780-842 (Stanford 1988), p. 233, who considers it possible that the identification of Thomas with Constantine VI was also an informal rumour.
6. Modern scholars estimate differently the degree to which social and financial conditions finally favoured Thomas’ rebellion. Especially Lemerle, P., "Thomas le Slave", Travaux et Memoires 1 (1965), p. 296-297, attributes a secondary role to these, underlining that similar discontent of the paysans can be traced in all periods. Others attribute the support to the rebellion to the dire socio-economical condition of the provinces. See Vasiliev, A.A., Byzance et les Arabes 1: La dynastie d'Amorium (820- -867) (Corpus Bruxellense Historiae Byzantinae I, Bruxelles 1968), p. 23-24. Hild, F. - Restle, M., Kappadokien (Kappadokia, Charsianon, Sebasteia und Lykandos) (Tabula Imperil Byzantini 2, Wien 1981), p. 77, attribute a social dimension to the revolt. Kopstein, Η., "Zur Erhebung des Thomas", in Kopstein, Η. — Winkelmann, V.F. (eds), Studien zum 8. und 9. Jahrhundert in Byzanz (Berliner Byzantinistische Arbeiten 51, Berlin 1983), pp. 61-87, believes that with Thomas' rebellion the provinces had a chance to express their discontent at the central administration.
7. It is possible that the theme of Anatolikon sided with Thomas because he had earlier served as a commander under the murdered Leo V. Kaegi, W.E., Byzantine Military Unrest 471-843 (Amsterdam 1981), p. 267, believes it equally possible that there was intense disgruntlement among the thematic troops towards the central administration on account of the suppression of Bardanes Tourkos’ rebellion.
8. Kaegi, W.E., Byzantine Military Unrest 471-843 (Amsterdam 1981), p. 266, mentions the strong personalities of the two generals who enforced loyalty to Emperor Michael II on their troops – Katakylas was a relative of his. Treadgold, W.T., The Byzantine Revival 780-842 (Stanford 1988), pp. 227-228, thinks that Leo V’s partition of the lands of the theme of Armeniakon undercut the loyalty he enjoyed, and as a result his successor was positively received.
9. According to Lemerle, P., "Thomas le Slave", Travaux et Memoires 1 (1965), p. 285-286, of the multitude of peoples mentioned as Thomas’ allies we can only be certain of that of the Iberians, Abkhazians and Arabs. The relations between these populations and Byzantium were particularly complicated in the early 9th century, making unclear the reasons behind their alliance to Thomas. It is possible, however, that the Armenians wished to avenge the murder of their compatriot Leo V, while the Abkhazians had during that period their attention turned to the west, often launching raids along the coasts of the Pontus.
10. Treadgold, W. Τ., The Byzantine Revival 780-842 (Stanford 1988), p. 229, mentions that the strategos of the Armeniakon Olbianos was leading that army. On the contrary, Lemerle, P., "Thomas le Slave", Travaux et Memoires 1 (1965), p. 286-287, believes that we can not extract any information on the first battle between Thomas and the forces of Michael II from the sources.
11. Treadgold, W. Τ., The Byzantine Revival 780-842 (Stanford 1988), p. 232-233, mentions that Thomas attacked the Arab lands of Armenia and conquered Theodosiopolis (Erzerum). Belke, Κ. - Mersich, Ν., Phrygien und Pisidien (Tabula Imperii Byzantini 7, Wien 1990), p. 92, estimate that the attack was launched further to the south, in Syria.
12. Χριστοφιλοπούλου, Αικ., Βυζαντινή Ιστορία 2.1: 670-867 (Θεσσαλονίκη 21993), p. 195, notes that Thomas could not shoulder the expenses for the upkeep of the thematic army and fleet only relying on the income from the public taxes, without the aid of the Arab caliph. Lemerle, P., "Thomas le Slave", Travaux et Memoires 1 (1965), p. 287, disagrees with the earlier estimate in Vasiliev, A.A., Byzance et lesArabes 1: La dynastie d'Amorium (820-867)(Covpus Bruxellense Historiae Byzantinae 1, Bruxelles 1968), p. 22-23, that Thomas’ alliance with the Arabs was so binding that al-Mamun could hope to subdue the Byzantine Empire through it.
13. Treadgold, W. Τ., The Byzantine Revival 780-842 (Stanford 1988), p. 236, attributes the enthusiasm of the inhabitants to the fact that they had been favoured by the pact of Leo V with the Bulgarians and were now reasonably willing to support the avenger of his murderer.
14. This was a nephew of Leo V who had been exiled by Michael II on Skoros and later had joined forces with Thomas.
15. Vasiliev A.A., Byzance et les Arabes 1: La dynastie d'Amorium (820- -867) (Corpus Bruxellense Historiae Byzantinae I, Bruxelles 1968), p. 40, more specifically situates it between the Hebdomon suburb and the Golden Gate.
16. Lemerle, P., "Thomas le Slave", Travaux et Memoires 1 (1965), p. 279-281, considers the testimony of the Byzantine sources, that the Bulgarians interfered in the internal affairs of the Byzantine Empire of their own accord, to be an echo of Michael II’s propaganda. Treadgold, W. Τ., The Byzantine Revival 780-842 (Stanford 1988), p. 240 agrees with him. Vasiliev, A.A., Byzance et lesArabes 1: La dynastie d'Amorium (820-867) (Corpus Bruxellense Historiae Byzantinae 1, Bruxelles 1968), p. 41, and Jenkins, R.H.J., Byzantium: The Imperial Centuries (AD 610-1071) (London 1966), p. 143 believe otherwise.
17. Treadgold, W. Τ., The Byzantine Revival 780-842 (Stanford 1988), p. 240, mentions that Thomas spent the winter in Arcadiopolis.
18. In the Theophanes Continuatus, ed. I. Bekker (Bonn 1838), p. 68.4, Adrianople is erroneously mentioned.
19. Treadgold, W. T., The Byzantine Revival 780-842 (Stanford 1988), p. 231.