The katepáno first appears in the 9th century, when it was used in the generic sense of "the one in charge" by two officials: the head of the basilikoi anthrōpoi ("imperial men"), a class of low-level court functionaries, and the head of the Mardaites marine detachments of the Byzantine naval theme of the Cibyrrhaeots in southern Asia Minor.
The reconquered frontier zones were divided into smaller themata, and grouped together to form large regional commands, headed either by a doux ("duke") or a katepanō.
[2] These were the ducates/katepanates[3] of Antioch, covering the south-eastern frontier in northern Syria, of Mesopotamia in the east around the Euphrates, and of Chaldia in the north-east.
[5] With the catastrophic territorial losses suffered during the 11th century, the office disappears in the sense of the overall military commander, but is retained in a more local level: during the Komnenian and Palaiologan periods, the term katepanikion thus comes to denote low-level administrative areas, both in Asia Minor (including the Empire of Trebizond) and Europe.
In the Palaiologan era, the katepanikion was governed by a kephalē (Greek: κεφαλή, "head"), who had supreme civil and military authority within its bounds.