The 'strategos' was appointed by the Emperor and exercised supreme military and political authority in the region of his jurisdiction. Each theme was divided into smaller administrative districts, and its troops were mainly recruited from the local peasantry. The first themes must have been created in the provinces of the East in the 2nd half of the 7th century, in order to deal more effectively with the various problems of defence there, since under the new system the 'strategos' in charge was invested with both military and political power.
By the 9th century the system of themes had been extended to the rest of the Empire, in an endeavour by the emperors to weaken the all-powerful governors of the earlier dioceses. However, the uniting of the two authorities in the person of one 'strategos' once again created all-powerful local lords who posed a threat to the central authority.
From the second half of the 11th century the emperors tried to face this danger through the separation of political from military authority and the continuous fragmentation of the large themes into smaller administrative districts ('katepanikia'). The 'strategoi' became simple commanders of army divisions and the term "theme" now denoted only geographical regions or small fiscal departments. After the capture of Constantinople by the Crusaders (1204) the theme organization collapsed.
The term thema was first applied to the Roman legion as George Finley quoted (page 12). The military districts, garrisoned by legions, were then called themata, and ultimately the word was used merely to indicate geographical administrative divisions.-- Ducange, Glossarium med. et inf. Graecitatis.
The number of themes varied at different periods.
The Emperor Constantine Porphyrogenituswriting about the middle of the 10th century, counts 16 in the Asiatic portion of the empire, and 12 in the European. 7 great themes are particularly prominent in Asia Minor, Optimaton, Opsikion, the Thrakesian, the Anatolic, the Bukellarian, the Kibyrraiot, and the Armeniac. In each of these a large military force was permanently maintained, under the command of a general of the province and in Opsikion, the Thrakesian, and the Kibyrraiot, a naval force was likewise stationed under its own officers.
The European provinces were divided into 8 continental and 5 insular or transmarine themes, until the loss of the exarchate of Ravenna reduced the number to twelve. Venice and Naples, though they acknowledged the suzerainty of the Eastern Empire, acted generally as independent cities. Sardinia was lost about the time of Leo's accession, and the circumstances attending its conquest by the Saracens are unknown.
The twelve European themes were--
- Longibardia (Calabria.)
The islands of the Archipelago, which formed the 16th Asiatic theme, were the usual station of the European naval squadron, under the command of a Drungarias. They are often called Dodekannesos, and their admiral was an officer of consideration at the end of the eighth century.--Theophanes,383 . The list of the themes given by Constantine Porphyrogenitus is a traditional, not an official document. Cyprus and Sicily had been conquered by the Arabs long before he wrote.
The Asiatic themes were--
- Anatolikon, including parts of Phrygia, Lycaonia, Isauria, Pamphylia, and Pisidia.
- The Armeniac, including Pontus and Cappadocia.
- The Thrakesian, part of Phrygia, Lydia, and Ionia.
- Opsikion, Mysia, and part of Bithynia and Phrygia.
- Optimaton, the part of Bithynia towards the Bosphorus.
- Bukellarion, Galatia.
- Chaldia, the country about Trebizond.
- Mesopotamia, the trifling possessions of the empire on the Mesopotamian frontier.
- Koloneia, the country between Pontus and Armenia Minor, through which the Lycus flows, near Neocæsarea.
- Sebasteia, the second Armenia.--Scrip. post Theoph. 112.
- Lycandos, a theme formed by Leo VI. (the Wise) on the borders of Armenia.
- The Kibyrraiot, Caria, Lycia, and the coast of Cilicia.
- The Aegean. Cappadocia is mentioned as a theme.--Scrip. post. Theoph. 112; and Charsiania, Genesius, 46. They had formed part of the Armeniac theme.
George Ostrogorsky in (The Byzantine Background of the Moravian Mission, pages 6-7) mention as about the European Themes and more specific in the Macedonian geographical boundaries......
At one extremity the process embraced Greek territory. Probably by the end of the eighth century the new theme of the Peloponnesus was created alongside the existing one of Hellas. The theme of Cephalonia, including the Ionian Islands, was organized in the first years of the ninth century at the latest.' At the other extremity, between 789 and 802, the theme of Macedonia was established, more or less contemporaneously the Greek themes to the south.
The Macedonian theme, however, had nothing in common with either classical Macedonia or that of modern times: this point must be made clear, particularly because the question of Macedonia is of especial importance to our problem. The Byzantine theme of Macedonia consisted of western Thrace, with its center at Adrianople. The name "Macedonia" was attached to this territory precisely because actual Macedonia was lost to Byzantium, and was occupied by Slavs and formed a conglomeration of Sclaviniae.
In the first half of the ninth century-probably in its early years-the regions of Thessalonica and Dyrrachium were organized as themes. Both, along with the themes mentioned above, are cited in Uspenskij's Tacticon, compiled between 845 and 856. On the other hand, Dvornik has pointed out that the Life of St. Gregory Decapolites, which he edited, already mentions, about 836, the strategus of Thessalonica and his protocancellarius; from which Dvornik rightly concluded that the theme of Thessalonica originated at least before 836.
The establishment of a theme in the Dyrrachium region probably took place in the first quarter of the ninth century, as was recently shown by Jadran Ferluga, who relied on an item of information in the correspondence of Theodore the Studite.ll The institution of themes in the territories of Thessalonica and Dyrrachium was a particularly important step in strengthening the Byzantine position in the Balkans, since Dyrrachium was the main base of the Empire on the Adriatic coast, and Thessalonica was both the main stronghold on the Aegean Sea and, what is of particular importance in the present context, the Empire's principal gateway to the Slavic world. Hence, on the eve of the great mission of the brothers from Thessalonica, this city became the center of the most important theme of the Empire in the Balkans.
Then Thessalonica was connected with the Thracian themes of Macedonia and Thrace by the creation of the theme of Strymon: this theme followed the coast between the rivers Strymon and Nestos, and its center was Serres. At the other extremity, the formation of the Nicopolis theme, in Epirus, completed the network of the theme system on Greek territory.
Finally, at the beginning of the reign of Basil I, the former archontia Dalmatia, which included the coastal cities and the nearby islands, acquired greater importance and was raised to the status of a theme. This was a decisive moment in the expansion of Byzantine influence in the western part of the Balkan Peninsula and in the Christianization of the Serbian lands.
- George Ostrogorsky,The Byzantium State
- George Ostrogorsky,The Byzantine Background of the Moravian Mission)
- George Finley, History of the Byzantium
- Al Vasilyev, A History of the Byzantine Empire