Oblun is situated near the eastern coast of Malo blato (Small Mud) of Skadar Lake . The fortification occupies a dominant position controlling a great part of Skadar Lake basin and the field of Cemovsko .

Oblun was mentioned as «intravit in castellum, qui Obolon dicitur» in the Chronicle of the priest of Doclea in reference with events in Doklea in the mid 12th century . According to the chronicle, king Ðordje, fleeing over mountains finally settled in a castle called Obolon, where the Byzantines, after having besieged and conquered the castle, took him a prisoner.

The fortification lies on the remains of acropolis of an Illyrian-Greek town. The preserved remnants of the fortification are assumed to date from the antique, late Roman or Byzantine periods, judging by their quite regular rectangular shape, although the terrain configuration does not allow for such a shape. The length of the completely preserved side on the northeast is about 70m. The northwestern and southeastern walls have been partly preserved, while there are no traces of a wall on the southwestern side. It probably did not exist there because it was replaced by vertical rocks. In the very centre of the fortification, on a separate, naturally elevated rocky plateau, the remains of a single-nave church can be found. An interesting fact is that no traces of towers have been discovered.