In official Byzantine use, the term is non-technical, and used in a descriptive manner, being generally applied to the defenders as well as the inhabitants of the eastern frontier zone, including their Muslim counterparts.
The popular image of the Akritoi has been heavily influenced by their portrayal in the Acritic songs, and refers to the military troops stationed along the Empire's border.
In case of a major Arab raid (razzia), they were supposed to raise the alarm, assist in the evacuation of the local population to the various strongholds, and shadow and harass the enemy force until reinforcements could arrive.
The Akritai declined in importance by the late 10th century, as the Byzantine conquests pushed the border eastwards, and its defense radically restructured, with smaller themata grouped in five large regional commands headed by a doux and a heavy presence of professional troops (tagmata).
The institution, in the form of a force raised by local inhabitants in exchange for land and tax exemptions, was re-established under Manuel I Komnenos (r. 1143–1180), when he reorganized the themes in the reconquered western portion of Asia Minor.