1. Derivation of the Term ‘Theme’

The term ‘theme’ refers to the military and administrative unit of the middle Byzantine period under the authority of a strategos. However, the scholars dispute over the origin and significance of this term as well as its evolution to its widely known form. At times various opinions have been expressed by the scientists dealing with the issue about the origin and significance of the word ‘theme’. G. Ostrogorsky1 attributes meanings like ‘placed’, ‘installed’ and ‘colonised’ to the term and believes that this was the name of the military unit settled in an area. Then, the name of the unit was also given to the place of settlement and, therefore, the term acquired a geographical and administrative aspect. Α. Pertusi2 attributed the meaning of ‘consigned’ and ‘deposited’ to the term and connected it with the location where the soldiers gathered, that is, the camp. S. Kyriakidis3 also argued that the ‘theme’ was the camp where the soldiers slept and that the military corps took its name from it. H. W. Haussig4 suggested an alternative interpretation for the origin and the significance of the geographical term ‘theme’. He believes that the term resulted from the creation of permanent winter military bases, which until then usually moved from one place to another. The creation of these bases was necessary in order to deal with the raids of nomads, which always took place during the fall and the winter. As for the name of the military unit, Haussig argues that it resulted from the military rolls and especially from the rolls of the Armenian provinces.

The aforementioned opinions of Pertusi, Haussig and Kyriakidis basically connect the term ‘theme’ with the camp and, therefore, with the unit settled there.Further research on this matter showed that this connection was weak and the aforementioned views were rejected.5 The concept of ‘theme’ as a military camp cannot be traced in the sources of the Byzantine period from the 3rd until the 7th century and, as a result, it cannot be proved. Apart from that, the unit ‘theme’ was not concentrated at one camp, but its soldiers were allocated among several camps of the wider area where the unit was settled. Consequently, there is no relation between the name of the unit and the camp of settlement. The origin of the theme, as a geographical term assigned to the fixed winter bases of the Byzantine army against the raids of the nomadic tribes, must also be rejected, as these camps, which were not fixed in their totality, were created in the western part of the Empire (Balkans, Italy), which was attacked by nomadic tribes (such as the Avars) usually during the fall and the winter. Nevertheless, the themes first appeared as an institution in Asia Minor, where the enemies of the Byzantines (Persians, Arabs) conducted warfare from spring until fall. Moreover, no source proves that the theme as a military unit results from the military lists and, therefore, the assumption still remains.

F. Dölger6 argued that the term ‘theme’ comes from the Greek word ‘thesis’, meaning a volume including records and concerning military lists where the soldiers of a unit were recorded; the volume was kept at the logothesion tou stratiotikou. The name ‘thesis’ of the records was originally given to the military unit entered into the record and then to the area where the unit was stationed. J.D. Howard-Johnston7 expressed the opinion that the ‘theme’ originates from the Mongolian word tymen or tümän denoting a military body of 10,000 men. This opinion, regardless of the question of the word’s origin, follows the traditional trend in research, according to which the term ‘theme’ was originally used in the names of military units and, therefore, denoted the area of settlement. The latest theory regarding the evolution of the term ‘theme’ is opposed to this trend. J. Koder8 argues that the word ‘theme’, given its etymological connection with the Greek verb τίθημι (tithemi), meaning to pose or to place, and taking under consideration the way in which the term was used in the sources until the 7th century, meant the area of settlement-jurisdiction, that is, the area where someone is ordered to settle, though not necessarily being a military settlement. As a result, it is highly likely that the settlement area of an entire military unit was characterised as ‘theme’, meaning the area where the military unit was stationed and for which this unit was responsible, from a military point of view. The area called ‘theme’ later gave its name to the military corps settled there.

2. The Establishment of ‘Themes’

The majority of scholars date the appearance of the ‘themes’ to the first half of the 7th century. Three major theories have been expressed regarding the creation of the new military and administrative unit. The first theory, which is attributed to G. Ostrogorsky,9 argues that the ‘themes’ were created during the reign of Emperor Herakleios (610-641), shortly before or immediately after the war against the Persians (620-628), and were a military and administrative reform introduced by the emperor. The army was reorganised in large military units called ‘themes’, which were stationed in Asia Minor in administrative units also called ‘themes’. The military and political power came to the hands of the person in charge of the military unit, that is, the strategos. The soldiers of the ‘themes’ were given the so-called ‘landed property’ by the imperial government in the area of their settlement. The income from this property enabled them to earn their living and purchase their armature. They had the right to bequeath the land to their children. This view, based on the anachronistic appearances of the term ‘theme’ in Chronographia of Theophanes regarding the years of Herakleios, has been refuted.10 I. Karayannopulos11 formulated a second theory regarding the creation of the ‘themes’ and suggested that the origin of the institution of "themes" should be traced back to the Early Byzantine period and in particular the 6th century, when the first examples of a union between the military and the political power under the military commander of the exarchates appeared. Because of the fact that the military landed property and, therefore, the institution of soldiers-farmers is evidenced by the sources only in the 10th century, he also believed that the themes probably had not existed before the 9th century. This view is partly questioned by the latest theory about the establishment of the ‘themes’. According to R.J. Lilie,12 the appearance of the ‘themes’ should be placed in the second third of the 7th century and should be considered a consequence of the Arab attack and the resulting new conditions on the eastern border of the empire.

After the first bitter defeats of the Byzantines and the fall of the eastern provinces (Syria, Palestine, Mesopotamia and Armenia) to the Arabs from 634 to 640, the armies of these areas retreated to Asia Minor. The magister militum per Orientem and his forces retired from Syria and Palestine to the lands which would later become the theme of Anatolikon, while the magister militum per Armeniam retired to the area which would later become the theme of Armeniakon. After the fall of Egypt to the Arabs in 642, the Byzantines lost their capability to counter-attack and regain the lost territory and, therefore, their armies were permanently settled in Asia Minor. The apparent weakness of the army to prevail over the Arabs in the open battlefield and stop the invasion of Asia Minor led to the distribution of the soldiers among the provinces where they had settled. A defensive war, whose priority was to block the invasions and prevent casualties and loss of territories, was escalated. By the mid-650, the reorganisation and permanent settlement of the Byzantine forces in Asia Minor territories must have taken an organised form. Four areas of military responsibility were created, which were called Anatolikon theme, Armeniakon theme, Opsikion theme and Thrakesion theme. The forces of magister militum per Orientem formed Anatolikon theme, while the armies of magister militum per Armeniam formed Armeniakon theme. The forces of the two magister militum Praesentalis, which formed Opsikion theme, and the forces of magister militum per Thraciem, which formed Thrakesion theme, were settled in Asia Minor mainland. These units served as reinforcements to the two border units, while they also undertook the defense of Constantinople and western Asia Minor respectively. Originally, the term ‘theme’ referred to the military unit under the orders of a strategos, which defended the area of its settlement. In the course of time, possibly towards the late 7th or in the early 8th century at the latest, this name was also given to the military district.

3. Soldiers – Farmers. A Major Institution in the Operation of ‘Themes’

The issue of soldiers-farmers and the military landed property also involves a long process of evolution in the course of time, from the second half of the 7th century until the 10th century. After the settlement of soldiers in the Asia Minor territories and due to the serious financial problems the Byzantine state had to face because of the wars and the loss of territories in the first half of the 7th century,13 the soldiers started to bond with the land where they were settled. The long stay of the soldiers in one place due to the defensive war against the Arabs favoured their connection with the local population and, therefore, the investment of the money they earned from their military service; they purchased land. Such an investment must have been initially well received by the imperial government as, in this way, a great part of the arable land, which had remained unexploited due to the reduction in the population in the 7th century (wars, epidemics), would be cultivated again and would yield tax revenues to the state. In good time, the state must have also ceded or sold land to the soldiers, aiming to create soldiers who would no longer be regularly paid for their military services, but would cover their needs, to a great extent, through the cultivation of their land. These soldiers were no longer professionals as, due to their being farmers as well as soldiers, they did not serve actively throughout the year, but only during military operations and according to the occasional needs. The soldiers probably started to bond with the land in the mid-7th century, while the whole process lasted for more than 2 centuries and was completed in the 10th century with the formation of the so-called military landed property, which was linked to the military service and was protected by imperial legislation, as it was officially ceded by the state. The conditions in the second half of the 7th century (financial problems and permanent settlement of soldiers in one place) favour the assumption that the largest part of the soldiers of the themes was not professionals but soldiers-farmers as early as in early 8th century.

4. The Themes in the 7th century

The first four military themes, Anatolikon, Armeniakon, Opsikion and Thrakesion, as well as the naval theme of Karabisianon, are recorded by sources in the second half of the 7th century. The theme of Armeniakon is mentioned for the first time in Theophanes’ Chronographia in 667.14 Another reference to the theme of Anatolikon is made in 669.15 The theme of Opsikion is mentioned for the first time in 680 in the lists of the officers who accompanied Emperor Constantine IV (668-685) in the Sixth Ecumenical Council.16 The theme of Thrakesion appears in 687 in the iussio of Emperor Justinian II to the Pope regarding the validation of the minutes of the Sixth Ecumenical Council, where the naval theme of Karabisianon is also mentioned.17 These dates, of course, are in no way the dates when these themes were established. As mentioned above, the creation of the themes was a long process, which started with the appearance of the Arabs (634) and took its first organised form in the sixth decade of the 7th century (650-660).

The reorganisation of the army in themes, because of the new conditions in the Near East after the appearance and prevalence of the Arabs, mostly aimed to create an effective defense against the continuous invasions of the new opponent, whose purpose was to occupy Asia Minor and dissolve the empire.18 Within this framework, the theme of Anatolikon took over the defense against the Arabs attacking from Syria and Palestine, while the theme of Armeniakon dealt with the Arabs of Mesopotamia. The theme of Opsikion comprised the expeditionary forces of the emperor, while at the same time it was responsible for the defense of the areas where it was settled (central and northwest Asia Minor) as well as Constantinople.19 The theme of Thrakesion undertook the defense of west Asia Minor, while it also assisted the borders against invaders. Finally, the theme of Karabisianon, which included the southwest Asia Minor coastline and the islands of the Aegean Sea, provided the provincial fleet of the empire. The organisation of this theme can be placed in 650, when the Arab fleet was also organised and activated in the southeastern Mediterranean.

The expansion of themes over the European territories of the empire appears to have started in the third quarter of the 7th century. The first European theme was the theme of Thrakesion, dating to 680.20 Its organisation by Emperor Constantine IV (668-685) probably aimed to the better defense of the capital against the Bulgarians, who had recently settled to the northeast of the Balkan peninsula.21 The establishment of the theme of Helladikon also dates to the late 7th century (698). This theme was the capstone of the campaigns launched by three emperors (Constans II in 656, Constantine IV in 678 and Justinian II in 688) in the second half of the 7th century, through which they managed to reinstate the Slav-occupied areas of central Greece under Byzantine control. Finally, the establishment of the theme of Kibyrraioton, which came from the theme of Karabisianon, as well as the organisation of the theme of Sicily in Italy, can be placed in the same period.

5. The Themes in the 8th Century

The first changes in the institution of themes, on both a military and administrative level, can be traced back to the 8th century. Until the end of the 7th century, the theme had already taken the form of a military district, where the strategos was responsible for the military forces and the defense of its territories. The military authority, nevertheless, operated in parallel with the civil, therefore leading to an inevitable overlapping of responsibilities. The needs of the defensive war conducted by the Byzantines, which in the greatest part of the second half of the 7th century and the first half of the 8th century resembled a guerrilla war aiming to keep the invaders out of Byzantine territory without having to go into battle and with the least possible losses in soldiers and non-combatant population,22 probably dictated, from the first years the themes were established, the transfer of all the jurisdictions of the civil administration directly concerning the safety of the population and the cities to the hands of the military administration, that is, the strategos. The need for the best possible handling of the Arab situation in combination with the gradual transformation of the themes into basically military administrative units, favour the assumption that the strategos, always within the framework of a long process, undertook increasing responsibilities for the civil administration of the provinces of his military district. As a result, towards the mid-8th century the military administration prevailed over the civil administration within the theme.23

The first change in the organisation of the four great Asia Minor themes took place in the early years of the reign of Constantine V (741-775). On the occasion of the revolt of the comes of the theme of Opsikion, Artabasdos (741-742/3), the emperor proceeded to the dissolution of this theme, after Artabasdos had prevailed. Until then the theme of Opsikion was the largest theme in Asia Minor. Its geographical position (near Constantinople) and its operation as an expeditionary force, within the framework of the system of themes, made the head of this theme the most powerful, both politically and militarily, among the strategoi of the themes. Constantine V removed a great part of the theme of Opsikion from its eastern side and created the Theme of Boukellarion, while a smaller part of the Asia Minor coastline across Constantinople formed the Theme of Optimaton. These two themes are first mentioned by sources in 768 and 775 respectively. However, their establishment should be placed in the years after Artabasdos’ revolt.24 Parallel to this development was the estblishement by Constantine V of a new military corps, the imperial tagmata of Constantinople.25 At first, they were two military units, the tagmata of schools and the excubitores, manned by selected professional soldiers of the themes of Anatolikon and Thrakesion, which had supported the emperor against the usurper. These units settled in the outskirts of Constantinople, were paid and equipped by the emperor and were, therefore, his personal army, regardless of the themes and the power of the strategoi. The strategoi, having complete control of the armies in their districts and acting, to a great extent, at their own free will in their themes, due to the special conditions the confrontation with the Arabs had created in Asia Minor, influenced powerfully the political situation of the empire in the second half of the 7th century until the reign of Constantine V, as proven by the great number of revolts against the central authority and the ascension of strategoi to the imperial throne. Therefore, the creation of the tagmata was an effort of the imperial government to reduce their political power and create a military counterbalance to the themes under its direct control.26

Apart from the themes of Boukellarion and Optimaton, the naval themes of the Dodecanese and Crete, which were possibly established around the middle of the century, are also reported among the new themes of the 8th century.

6. Division of Large Themes and Expansion of the Institution in the 9th Century

In the 9th century there was a multiplication of themes in the Balkan territories of the empire and, in particular, in the territory of modern Greece. According to records, the theme of Macedonia was established in 802 in the territory of modern western Thrace, the theme of Cephallenias in 809, the theme of the Peloponnese in 811 and the theme of Thessaloniki in 824. The successful campaigns of Emperor Constantine V in 758/759 against the Sclavenians in Macedonia, of Stavrakios, logothetes tou dromou, in 783, who completely subordinated Macedonia and central Greece and went as far as the Peloponnese, and of strategos Skleros in 805, who completely subordinated the Peloponnese, allowed the Byzantines to regain full control of the Greek territory and organise it, both militarily and politically, according to the system of themes.27

When the Amorian dynasty ascended to the throne in 820, there were changes in the system of themes in Asia Minor, which resulted in the division of the large old themes into smaller ones, while at the same time new themes were established in the Balkans under Byzantine control. The diminution of Asia Minor themes, which meant that they became geographically equal to the provinces of civil administration, was the basic step towards the completion of the themes as administrative units, where the civil and military administration was integrated and fully exercised by the strategos. Nevertheless, this development, along with the strengthened positions the strategoi held within their themes, signified their political castration and their downgraded role in the army. From the 9th century onwards, the strategoi of the themes gradually stopped influencing political developments in Constantinople and appearing as the heads of expeditionary forces. This role was undertaken by the domestikos ton scholon, that is, the head of the imperial orders of Constantinople, which gained a prominent position in the army, as a chosen and basic force.

The theme of Chaldia (possibly in 824) and the theme of Paphlagonia (possibly in 826) were established during the reign of Emperor Michael II (820-829) and included territories from the theme of Boukellarion and the theme of Armeniakon. The reign of Emperor Theophilos (829-842) included the establishment of the theme of Cappadocia in 830 in the east part of the theme of Anatolikon and the theme of Chersonos in 833. The theme of Charsianon (possibly in 863) and the theme of Colonea were established during the reign of Michael II (842-867) and included territories of the theme of Armeniakon. The theme of the Egean (842) and the theme of Dyrrachion (856) were also established. During the reign of Basil I (867-886), founder of the Macedonian dynasty, the theme of Leontokomis-Tefrikis (879) was established thanks to the return of these areas under Byzantine control after the emperor had managed to defeat the Paulicians settled there. Finally, the theme of Strymon (899) and the theme of Nikopolis (899) as well as the theme of Dalmatia (878) were also created in the Balkans during the reign of Leon VI. Moreover, the theme of Lombardia (892) was created in Italy (892), while the naval theme of Samos was established in 899.

A new military administrative unit called kleisoura appeared in the 9th century. The kleisoures were mountain passes organised according to the standards of the themes, though on a much smaller scale. The territories of the kleisoura were under the control of the kleisourarches and aimed to better organise the defense of mountain passes used by the enemies of the Byzantines in Asia Minor. The areas of Charsianon, Cappadocia and Seleukeia were organised in ‘kleisoures’ before they were promoted to themes.

7. The Theme as an Administrative Unit

The evolution and consummation of the theme as an administrative unit was the result of a long process, which lasted for more than two centuries. In the 7th century, the civil administration of the provinces forming the empire throughout the Late Roman period, which were more and smaller than the new military districts, continued to operate independently of the military administration of the wider military districts. Only during the 8th century did the strategos, as the head of the military district, start to supervise the administration of the provinces that were near the borders of his military district, while the full union between the military and the civil authority within the framework of the theme under the strategos took place in the 9th century.

There is plenty of information available in the sources28 of that period about the consummation of the long process of the evolution of themes to administrative units in the 9th and the 10th century as well as of their administrative and military structure. Depending on its size, the theme was usually divided into two to four tourmai under the tourmarches. The tourmai were subdivisions of the military unit of theme as well as of the administrative unit of theme. The military unit of a tourma, in turn, was divided into droungoi, under the droungarios, while the droungoi were subdivided into banda under a comes. The military and the civil administration of the theme was the jursdiction of the strategos, who was usually appointed for a period of 3-4 years. The political administrative centre of the theme was the base of the strategos, that is, the capital of the theme. The basic political subordinates of the strategos, who came from the central services of Constantinople, were the following: the praetor or judge (krites) of the theme, who undertook to try civil and penal cases together with the strategos, the chartoularios, who maintained the soldiers’ registry and reported to the logothesion tou stratiotikou,29 the protonotarios, responsible for the civil administration and the collection of taxes in the form of commodities useful for the army, who was subordinate to the secreton of sakellion, the commanders, the exisotai and the supervisors, who were under the logothesion tou genikou and were responsible for the land inventory as well as the determination and collection of tributes.

The legislation of the Byzantine emperors in the 10th century concerning the protection of the so-called military landed property was the main source of information about the institution of soldiers-farmers in the framework of the theme.30 The armies of the themes, which in the 10th century comprised from 4000 to 15,000 men, included partly professional soldiers settled in both the base of the strategos and the strategic cities-fortresses within the theme, who were always on the alert, and partly soldiers-farmers settled in landed properties ceded to them by the imperial government under obligation of military service.31 This landed property was entered in the military registries and their owner was relieved of any special taxation as long as he provided for a military horse and the armature of a soldier. In case he was called to provide military services, the owner of the military landed property had either to turn up and offer his unpaid services or, in case he could not exercise his duties, to pay the amount which corresponded to the employ of a mercenary. The obligation of military service was hereditary, as it was not connected with the person but with the land. It is obvious that soldiers-farmers were not in a state of constant readiness throughout the year like professional soldiers, but mostly during the operations (from spring to fall).

8. The Themes in the 10th Century

The increase in number of the themes in Asia Minor continued during the first half of the 10th century, when new themes were created in territories occupied again by the Byzantines on the eastern border. Therefore, the theme of Mesopotamia and the theme of Sebasteia in 911 as well as the theme of Lykandos were established in 916. The theme of Seleukeia was created in 934 to the east of the theme of Anatolikon and the theme of Harpezikion in 949. Finally, the theme of Crete was created anew in 961, after the island was recaptured by the domestikos of the schools of the east, Nikephoros Phokas, while the theme of Cyprus was created in 965, after the island was annexed to the Byzantines.

Slowly but steadily the themes on the borders of Asia Minor started to disintegrate from the mid-10th century onwards and, as a result, the military role of the theme was downgraded.32 The new, small themes, also known as Armenian, were formed around cities-fortresses and had a small number of infantry soldiers. These themes had mostly a defensive character, as their infantrymen were scattered across the borders and, thus, could successfully impede the Arab invasions. The military reform of Emperor Nikephoros II Phokas (963-969),33 which led to the creation of the duchies on the imperial eastern border, in combination with the multiplication of the strategoi of the cities-fortresses,34 completely downgraded the military and administrative role of the theme. The administration of the duces / doukes or katepano were based on the multiplication of the number of the tagmata and, therefore, on the number of professional soldiers in the army. The dux or katepano supervised a wider area called duchy or katepania, which included more themes, therefore further weakening the strategoi of the themes. The units of the imperial tagmata, whose number was multiplied in the 10th century, were settled in the base of the doukas or katepano. These tagmata helped the soldiers of the themes defend the borders, when the latter could not deal with the enemy on their own, while they also gave their commanders the chance to attack, without waiting for reinforcements from Constantinople. The system of the duchies or katepaniai started in Asia Minor, but soon, possibly during the reign of John I Tzimiskes (969-976), expanded to the Balkan territories and the Italian possessions of the empire.

9. The Decline of the Institution of Themes and their Extinction

In the late 10th century the strategos controlled a much smaller territory around a castle. That meant the restriction of both his political power, which gradually came to the hands of the civil officials of the theme, and his military power, as now a much smaller number of soldiers would be under his orders. Since the third quarter of the 10th century, the doukes or katepano controlled all the troops within their district, while in the 11th century they gained political power as well. At this time, the strategos lost the civil administration of the theme, as the judge or praetor was considered from then on the civil governor of the limited territory of the theme; he exercised judicial power and collected the taxes.35 From the mid-11th century onwards, this development, on both a military and a political level, resulted to the gradual extinction of any reference made by the sources to the strategoi of the themes. The themes started to denote geographical districts with a unified judicial and economic power, usually gathered in the hands of the judge or praetor.36

On a military level, the efforts of the Byzantine emperors in the 10th century to protect through legislation the small property and, therefore, the institution of soldiers-farmers, which was the basis of the army of the theme, seem to have been inadequate and could not prevent the gradual extinction of military landed properties, which came to the hands of great land owners.37 This development, in combination with the aggressive policy of the empire, which demanded the creation of more units of professional soldiers that could better answer the needs of the distant and long-term campaigns, completely downgraded the themes against the tagmata. The invasions of new enemies in the Balkans (Petsenegoi) and in Asia Minor (Seljuk Turks) in the 11th century completed the dissolution of the military structure of the empire, which was based on the themes. At that time, the number of tagmata was multiplied as they comprised to a great extent foreign mercenaries.38

The abolition of the institution of themes came in the 12th century. Nevertheless, the term was still used to characterise economic geographical units in the Late Byzantine period.39

1. Ostrogorsky, G., Die wirtschaftlichen und sozialen Entwicklungsgrundlagen des byzantinischen Reiches’, Vierteljahrschrift für Sozial- und Wirtschaftsgeschichte 22 (1929), p. 130.

2. Pertusi, A., ‘Nuova ipotesi sull’ origine dei 'temi' bizantini’, Aevum 28 (1954), pp. 126-150.

3. Κυριακίδης, Σ., ‘Πώς η λέξις θέμα έφθασεν εις την σημασίαν της στρατιωτικής περιοχής’, Επετηρίς Εταιρείας Βυζαντινών Σπουδών 23 (1953), pp. 392-394; the same, ‘Προσθήκη εις τα περί της ετυμολογίας και σημασίας της βυζαντινής λέξεως ΘΕΜΑ’,  Ελληνικά 13 (1954), p. 339.

4. Haussig, H.-W., Die Anfänge der Themenordnung, (Frankfurt 1957), pp. 90-114.

5. See argumentation in Karayannopulos, I., Die Entstehung der byzantinischen Themenordnung (München 1959), pp. 89-91.

6. Dölger, F., ‘Zur Ableitung des byzantinischen Verwaltungsterminus θέμα, Historia 4 (1955), pp. 189-198.

7. Howard-Johnston, J.D., ‘Thema’, in Moffatt, Α. (edit.), Maistor. Classical, Byzantine, and Renaissance Studies for Robert Browning, (Byz. Australensia 5, Canberra 1984), pp. 189-197.

8. Koder, J., ‘Zur Bedeutungsentwicklung des byzantinischen Terminus Thema’, Jahrbuch der Österreichischen Byzantinistik 40 (1990), pp. 155-165.

9. Ostrogorsky, G., Geschichte des Byzantinischen Staates (München 1952) [Ιστορία του Βυζαντινού Κράτους Β΄ (Athens 1981), pp. 163-165].

10. Karayannopulos, I., Die Entstehung der byzantinischen Themenordnung (München 1959), p. 16; Lilie, R.J., Die byzantinische Reaktion auf die Ausbreitung der Araber, Studien zur Strukturwandlung des byzantinischen Staates im 7. und 8. Jahrhundert (Miscellanea Byzantina Monacensia 22, München 1976), pp. 29-30.

11. Karayannopulos, I., Die Entstehung der byzantinischen Themenordnung (München 1959).

12. Lilie, R.J., Die byzantinische Reaktion auf die Ausbreitung der Araber, Studien zur Strukturwandlung des byzantinischen Staates im 7. und 8. Jahrhundert (Miscellanea Byzantina Monacensia 22, München 1976), pp. 287-321; the same, ‘Die zweihundertjährige Reform. Zu den Anfängen der Themenorganisation im 7. und 8. Jahrhundert’, Byzantinoslavica 45 (1984), pp. 32-39.

13. About the emergence of soldiers-farmers along with the work of Lilie, see also Hendy, M.F., Studies in the Byzantine monetary economy c. 300-1450 (Cambridge 1985), pp. 634-640; Haldon, J.F., Recruitment and conscription in the byzantine Army c. 550-950 (Wien 1979), pp. 66-79; the same, Byzantium in the seventh century - the transformation of a culture (Cambridge 1991), pp. 244-251.

14. Theophanes, Chronographiaedit. C. de Boor (Corpus Scriptoroum Historiae Byzantinae, Bonn 1883), p. 348.

15. Theophanes, Chronographia, edit. C. de Boor (Corpus Scriptoroum Historiae Byzantinae, Bonn 1883), p. 352.

16. Sacrorum Conciliorum Nova et Amplissima Collectioedit. J.D., Mansi, vol. XI (Florence 1759-1927), p. 209.

17. Sacrorum Conciliorum Nova et Amplissima Collectioedit. J.D. Mansi, vol. XI (Florence 1759-1927), p. 737; Lilie, R.J., “'Thrakien' und 'Thrakesion'”, Jahrbuch der Österreichischen Byzantinistik 26 (1977), 22f.

18. Lilie, R.J., Die byzantinische Reaktion auf die Ausbreitung der Araber, Studien zur Strukturwandlung des byzantinischen Staates im 7. und 8. Jahrhundert (Miscellanea Byzantina Monacensia 22, München 1976), pp. 83-85.

19. The operation of the theme of Opsikion as an expeditionary army of the emperor was largely restricted throughout the second half of the 7th century due to the numerous Arab raids, which often reached deep in the mainland and the western coasts of Asia Minor amnd, as a result, the soldiers of this theme were immobilised in the area of their settlement. About the operation of Opsikion with respect to the organisation of the themes, see Haldon, J.F., Byzantine Praetorians, (Poikila Byzantina 3, Bonn 1984), pp. 207-209.

20. About the chronology of themes, see Haldon, J.F., Warfare, State and Society, in the Byzantine World 565-1204 (London 1999), pp. 86-87.

21. The unsuccessful campaign of Constantine IV against the Bulgarians of Asparouch, who were stationed in the region between the Dniester and the Danube, led to the treaty of 681 and their settlement to the south, in Byzantine territories between the Danube and Mount Haimos. Νυσταζοπούλου-Πελεκίδου, Μ., Οι βαλκανικοί λαοί κατά τους μέσους χρόνους (Thessaloniki 1992), pp. 96-98.

22. Lilie, R J., Die byzantinische Reaktion auf die Ausbreitung der Araber, Studien zur Strukturwandlung des byzantinischen Staates im 7. und 8. Jahrhundert (Miscellanea Byzantina Monacensia 22, München 1976), p. 94. Haldon, J.F., Recruitment and conscription in the byzantine Army c. 550-950 (Wien 1979), p. 67.

23. The same opinion is held by Lilie, who realises the lack of information in the sources about this matter and believes that the reduced size of some big themes indicates this change on an administrative level (Opsikion, Anatolikon) in the mid-8th century. Lilie, R.J., Die byzantinische Reaktion auf die Ausbreitung der Araber, Studien zur Strukturwandlung des byzantinischen Staates im 7. und 8. Jahrhundert (Miscellanea Byzantina Monacensia 22, München 1976), pp. 310-311.

24. About the partition of Opsikion and the formation of two new themes, see Haldon J.F., Byzantine Praetorians (Poikila Byzantina 3, Bonn 1984), from p. 205 onward.

25. About the tagmata, see Haldon, J.F., Byzantine Praetorians (Poikila Byzantina 3, Bonn 1984), pp. 236-246; Kühn, H.J., Die byzantinische Armee im 10 und 11. Jahrhundert (Wien 1991), from p. 48 onward.

26. Γρηγορίου-Ιωαννίδου, Μ., Παρακμή και πτώση του θεματικού θεσμού (Thessaloniki 1985), p. 39.

27. Νυσταζοπούλου-Πελεκίδου, Μ., Οι βαλκανικοί λαοί κατά τους μέσους χρόνους (Thessaloniki 1992), p. 87.

28. The basic information comes from the work of Emperor Constantine VII Porphyrogenitus De Thematibus (On Themes) and the numerous Τactica (Tactics) of this period, that is, books on military tactic as well as the political and military organisation of the Byzantines, see list of sources.

29. Νυσταζοπούλου-Πελεκίδου, Μ., ‘Η ανόρθωση’ in Ιστορία του Ελληνικού Έθνους Η΄ (Athens 1979), p. 168.

30. About the Novellae of the Byzantine emperors concerning military land, see Ius Graecoromanum, edit. J.P. Zepos, I (Athens 1931 – Aalen 1962); Svoronos N., ‘Societe et organisation interieure dans l’ empire byzantin au XIe siecle: les principaux problemes’, in Etudes sur l’ organisation interieure, la societe et l’ economie de l’ Empire byzantin (Variorum Reprints, London 1973), ΙΧ, pp. 1-17; Lemerle, P., The Agrarian History of Byzantium, from the origins to the twelfth century. The sources and problems (Galway 1970); Kaplan, M., Les homes et la terre a Byzance du VIe au XIe siecle. Propriete et exploitation du sol (Paris 1992).

31. Γρηγορίου-Ιωαννίδου, Μ., Παρακμή και πτώση του θεματικού θεσμού (Thessaloniki 1985), pp. 110-121.

32. Γρηγορίου-Ιωαννίδου, Μ., Παρακμή και πτώση του θεματικού θεσμού (Thessaloniki 1985), p. 56.

33. Kühn, H.J., Die byzantinische Armee im 10. und 11. Jahrhundert (Wien 1991), pp. 123-135.

34. Γρηγορίου-Ιωαννίδου, Μ., Παρακμή και πτώση του θεματικού θεσμού (Thessaloniki 1985), pp. 57-78.

35. Γρηγορίου-Ιωαννίδου, Μ., Παρακμή και πτώση του θεματικού θεσμού (Thessaloniki 1985), pp. 85-89.

36. Γρηγορίου-Ιωαννίδου, Μ., Παρακμή και πτώση του θεματικού θεσμού (Thessaloniki 1985), pp. 96-102.

37. Fine, J.V.A., ‘Basil II and the decline of the Theme System’, Studia slavico-byzantina et medievalia Europensia, I (Ivan Duijcev Center for Slavo-Byzantine Studies, Sofia 1989), pp. 44-47.

38. Γρηγορίου-Ιωαννίδου, Μ., Παρακμή και πτώση του θεματικού θεσμού (Thessaloniki 1985), pp. 144-148.

39. Kazhdan, A., see entry ‘Theme’, The Oxford Dictionary of Byzantium (Oxford – New York 1991), p. 2035.