The Theme System

The theme system, also known as the themata, was the system of military and administrative organization that the Byzantine Empire developed in the seventh and eighth centuries in response to the catastrophic loss of the eastern and southern provinces to the Arab conquests. The system bound soldier-farmers to specific provinces in exchange for land grants, providing the empire with a reliable military force and a stable tax base. The theme system helped Byzantium survive the Arab invasions and recover much of its lost territory, and it remained the basis of the Byzantine military and administrative organization until the eleventh century, when the system gradually broke down and was replaced by a system of professional mercenaries.

The theme system was one of the most successful military and administrative innovations of the medieval world, and it has been the subject of intense scholarly study. To understand the theme system is to understand one of the principal reasons for the survival of the Byzantine Empire through the crisis of the seventh and eighth centuries.

The Background

The Crisis of the Seventh Century

The theme system was developed in response to the catastrophic crisis that the Byzantine Empire experienced in the seventh century. The crisis began in the 610s with the invasion of the empire by the Sassanid Persians, who captured Jerusalem in 614 and threatened Constantinople itself. The emperor Heraclius, who came to the throne in 610, was able to defeat the Persians, but the war had been devastating. The empire was exhausted, and the army, which had been the most powerful in the Mediterranean, had been largely destroyed.

The crisis was compounded by the sudden appearance of the Arab armies in the 630s. The Arab conquests, inspired by the new religion of Islam, were extraordinarily rapid. By the 640s, the Byzantines had lost Syria, Palestine, and Egypt, the empire’s richest provinces and the source of much of its grain supply. By the 670s, the Arabs were threatening Constantinople itself, and the empire was in danger of being absorbed into the new Arab empire.

The traditional late Roman system of military and administrative organization, which had been based on a large standing army of professional soldiers and a complex system of imperial administration, had collapsed under the pressure of the crisis. The empire could no longer afford to maintain a large professional army, and the imperial administration had been disrupted by the loss of the eastern provinces. The theme system was developed in response to this crisis, and it represented a fundamental reorganization of the empire’s military and administrative structure.

The Origins of the Theme System

The Soldier-Farmers

The origins of the theme system are obscure, and they have been the subject of intense scholarly debate. The traditional view, derived from the late Byzantine historian Constantine VII Porphyrogennetos, was that the theme system was the creation of the emperor Heraclius, who reorganized the empire’s military forces in the 620s in response to the Persian threat. According to this view, Heraclius divided the empire’s remaining territory into a number of military districts, the themes, each of which was governed by a strategos, a military commander, and each of which supported a military force composed of soldier-farmers.

The modern scholarly view, which has developed since the 1970s, is more cautious. While the theme system was in place by the eighth century, its exact origins are unclear, and it may have developed gradually over the course of the seventh century. The system may have had its roots in the late Roman practice of settling barbarian soldiers on imperial lands in exchange for military service, and it may have been adapted and refined in response to the Arab conquests.

Whatever its exact origins, the theme system was a fundamental reorganization of the empire’s military and administrative structure. The system bound soldier-farmers, known as stratiotai, to specific themes in exchange for land grants. The land grants, which were hereditary, gave the soldiers a personal stake in the defense of the empire, and the system provided a reliable military force at a relatively low cost.

The Strategos

The strategos, the military governor of the theme, was the central figure in the theme system. The strategos was appointed by the emperor, and he had both military and civil authority in the theme. He commanded the military forces of the theme, supervised the civil administration, and was responsible for the collection of taxes. The strategos was typically a member of the imperial aristocracy, and he was often a eunuch, who could not have heirs and who was therefore less likely to challenge the imperial authority.

The themes themselves varied in size and importance. The largest themes, such as the Anatolikon theme in central Anatolia, could support a military force of more than 10,000 men, while the smaller themes, such as the theme of Cyprus, could support only a few thousand. The total military force of the themes in the eighth and ninth centuries has been estimated at between 100,000 and 200,000 men, although the exact number is uncertain.

The themes were organized on the basis of the military forces they supported. The cavalry, the infantry, and the navy were each organized into separate themes, and the soldiers of each theme were expected to provide their own equipment, including horses, weapons, and armor. The system was designed to be self-sustaining, with the soldiers producing their own food and equipment on the land they had been granted.

The Development of the Theme System

The Eighth Century

The theme system was developed and refined in the eighth century, especially during the reign of the Isaurian dynasty. The Isaurian emperors, beginning with Leo III in 717, were the principal architects of the system, and they made several important innovations. First, they reorganized the themes, reducing the size of the largest themes and creating new themes in the newly recovered provinces. Second, they developed a system of professional reserves, the so-called tagmatic army, which was stationed in Constantinople and which could be deployed against the most serious threats. Third, they developed a system of fortified towns, the kleisourai, which served as bases for military operations against the Arabs.

The Isaurian period was also the period of the Iconoclast controversy, which had a major impact on the theme system. The Iconoclast emperors, who banned the veneration of icons, were able to use the wealth of the monasteries to fund the army and to support the theme system. The Iconoclast policy was thus closely tied to the military and administrative reorganization of the empire.

The Ninth and Tenth Centuries

The theme system reached its peak in the ninth and tenth centuries, especially during the Macedonian dynasty. The Macedonian emperors, beginning with Basil I in 867, presided over a great expansion of the empire’s territory, and the theme system was used to govern the newly recovered provinces. The themes were reorganized again, with the larger themes being subdivided and the smaller themes being created. The Macedonian period saw the development of a new type of soldier, the so-called “foreign soldier,” who was recruited from among the Armenians, the Slavs, and the Rus, and who served in the imperial army.

The Macedonian period also saw the development of a new type of military force, the so-called “heavy cavalry,” which was the elite of the Byzantine army. The heavy cavalry, which was recruited from among the Anatolian aristocracy, was the most effective military force in the Mediterranean, and it was the backbone of the Byzantine army until the eleventh century. The heavy cavalry was supported by the theme system, which provided the bulk of the army.

The Decline of the Theme System

The Eleventh Century

The theme system began to break down in the eleventh century, especially during the reigns of the so-called “soldier emperors,” the Macedonian rulers who came to the throne in the mid-eleventh century. The breakdown was caused by a number of factors, including the growth of the great estates, the rise of the provincial aristocracy, and the increasing reliance on mercenary forces.

The growth of the great estates was one of the principal causes of the breakdown. The theme system depended on the existence of a class of free, independent soldier-farmers, who owned their own land and who were bound to military service. The growth of the great estates, which were owned by the aristocracy, the church, and the monasteries, gradually dispossessed the soldier-farmers, who became tenants or laborers on the estates. The loss of the soldier-farmers meant the loss of the military forces of the themes, and the empire was forced to rely increasingly on mercenary forces.

The rise of the provincial aristocracy was another cause of the breakdown. The provincial aristocrats, who were often descendants of the old theme commanders, gradually built up their own power bases, and they were able to challenge the authority of the imperial government. The aristocrats were reluctant to provide military service to the empire, and they preferred to use their forces to defend their own interests. The breakdown of the theme system was thus closely tied to the rise of the provincial aristocracy.

The increasing reliance on mercenary forces was a third cause of the breakdown. The mercenaries, who were recruited from among the Normans, the Germans, the Turks, and the Slavs, were often more effective than the theme soldiers, but they were also more expensive and less reliable. The mercenaries had no personal stake in the defense of the empire, and they were often willing to switch sides if their pay was better. The reliance on mercenaries thus weakened the theme system, and it left the empire dependent on forces that were unreliable and expensive.

The Battle of Manzikert

The Battle of Manzikert in 1071 was the final blow to the theme system. The defeat of the Byzantine army at Manzikert, and the capture of the emperor Romanos IV Diogenes, led to the collapse of the theme system in Anatolia, and the empire lost much of its Anatolian territory. The theme system was never fully restored, and the empire was forced to rely increasingly on Western mercenaries, including the Crusaders, for its defense.

The collapse of the theme system had profound consequences for the Byzantine Empire. The empire lost its military forces, its tax base, and its recruiting ground in Anatolia, and it was forced to rely on a system of professional mercenaries, which was expensive and unreliable. The loss of the theme system was one of the principal causes of the long decline of the Byzantine Empire, and it contributed to the eventual fall of Constantinople in 1453.

The Legacy of the Theme System

Influence on Other States

The theme system had a significant influence on other medieval states, especially on the Slavic states of the Balkans and on the Kievan Rus. The Bulgarian state, the Serbian state, and the Romanian principalities all adopted elements of the Byzantine theme system, and the system became a model for the military and administrative organization of these states.

The theme system also had a significant influence on the Arab and Turkish states, which had been in contact with the Byzantines since the seventh century. The Arab and Turkish military and administrative systems drew on Byzantine models, and the theme system was one of the principal sources of inspiration for the organization of the Arab and Turkish states.

Modern Scholarship

The theme system has been the subject of intense scholarly study since the late nineteenth century, and it remains a major topic in the study of Byzantine history. The scholarly debate has focused on the origins of the system, its development and decline, and its significance for the survival of the Byzantine Empire. The modern view is that the theme system was a major factor in the survival of the empire through the crisis of the seventh and eighth centuries, and that its breakdown in the eleventh century was a major factor in the long decline of the empire.

The theme system has also been the subject of comparative study, especially in comparison with the feudal systems of medieval Western Europe. The Byzantine theme system, which was based on the principle of service in exchange for land, has been compared with the European feudal system, which was also based on the principle of service in exchange for land. The two systems developed independently, but they shared certain features, and they have been the subject of comparative historical analysis.

Conclusion

The theme system was one of the most successful military and administrative innovations of the medieval world. The system, which bound soldier-farmers to specific themes in exchange for land grants, provided the Byzantine Empire with a reliable military force and a stable tax base. The system helped Byzantium survive the Arab invasions and recover much of its lost territory, and it remained the basis of the Byzantine military and administrative organization until the eleventh century. The breakdown of the theme system in the eleventh century was a major factor in the long decline of the Byzantine Empire, and it contributed to the eventual fall of Constantinople in 1453. To understand the theme system is to understand one of the principal reasons for the survival of the Byzantine Empire through the crisis of the seventh and eighth centuries.

Related Articles

• The Macedonian Dynasty — the golden age of the theme system
• Byzantine Emperors — the rulers of the empire
• History of the Byzantine Empire — the broader context
• Byzantine Iconoclasm — the controversy of the Isaurian period
• The Battle of Manzikert — the disaster that ended the theme system