| Theme of Mesopotamia Μεσοποταμία, θέμα Μεσοποταμίας | |
|---|---|
| Theme of theByzantine Empire | |
| 899/900s–1070s | |
 Map of the Theme of Mesopotamia within theByzantine Empire in 1000 AD. | |
| Historical era | Middle Ages |
• Established | 899–911 |
• Fall to theSeljuks. | 17 May 1070 |
| Today part of | Turkey |
Mesopotamia (Greek:Μεσοποταμία) was the name of aByzantinetheme (a military-civilian province) located in what is today easternTurkey. It should not be confused with the region ofMesopotamia or with the older Roman and early Byzantineprovince of Mesopotamia. The Byzantine theme was located between the rivers Arsanias (modernMurat) and Çimisgezek.
The theme was formed probably between 899 and 911, when EmperorLeo VI (r. 886–912) appointed the formerproconsul of theProvince of Pontus, named Lucius, as its governor.[1][2] Most of the province was formed out the Georgian principality ofTaron, ruled by the chieftain Manuel Bagratiom. Manuel and his four sons were persuaded to cede their territory to the Byzantine Empire in exchange for titles and estates in other themes. The Armenian-populated districts ofKeltzene (detached from the theme ofChaldia) andKamacha (part of the theme ofKoloneia) were then joined to it to form the new theme.[3][4]
Although EmperorConstantine VII Porphyrogennetos (r. 913–959) mentions that before its elevation to a theme, the region was an "unnamedkleisoura", there is evidence of much earlier administrative structures than that.[4] A seal of a "spatharios andstrategos of Mesopotamia" has been dated to c. 810, perhaps indicating the existence of a first short-lived theme there, and a seal of atourmarches with the Armenian name Mousilikes, is tentatively dated to c. 870.[5]
It is thus possible that Mesopotamia was constituted in the late 9th century out of an Armenian principality as a division (tourma) of some neighbouring theme, with its prince receiving a Byzantine title and continuing to govern it, before it was expanded into a full theme. This may also explain the peculiar custom of itsstrategos drawing, until 911, his salary not from the imperial treasury but from the customs proceeds of thekommerkion of his province.[4]
Commanders of the theme continued to be appointed throughout the 10th century, co-existing with the new post of "doux of Mesopotamia", established c. 975. Unlike thestrategos, thedoux was a regional commander, controlling the central sector of Byzantium's eastern frontier.[2][6] In the 11th century, most of the attesteddoukes of Mesopotamia were Armenians, includingGregory Magistros and his son. In the aftermath of theBattle of Manzikert in 1071, EmperorMichael VII Doukas (r. 1071–1078) tried to re-establish Byzantine authority, but the province fell to theSeljuk Turks.[2]