5De Vismes Kane, William F. M. "The Black Pig's Dyke: The Ancient Boundary Fortification of Uladh." Proceedings of the Royal Irish Academy. Section C: Archaeology, Celtic Studies, History, Linguistics, Literature 27 (1908-1909): 303.
Kane presumed that the Dyke was intended to defend the Uladh from threats coming from the south due to fact that the rampart's slope was deeper to that direction. Later excavation added details regarding the greater height of the northern-most bank and ditch defenses. (Walsh, Aidan. "Excavation at the Black Pig's Dyke." Clogher Record 14.1 (1991): 9-26.)